The population of Mexico


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The population of Mexico its composition and changes
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xviii, 346 leaves. : ill. ; 28 cm.
Bridges, Julian C
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Population -- Mexico   ( lcsh )
bibliography   ( marcgt )
theses   ( marcgt )
non-fiction   ( marcgt )


Thesis--University of Florida.
Bibliography: leaves 334-344.
Statement of Responsibility:
by Julian C. Bridges.
General Note:
General Note:

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University of Florida
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Full Text






Copyright by
Julian C. Bridges

To my beloved wife and daughters,
whose patience, encouragement,
and assistance have made this
study possible


The writer recognizes his debt to many people for

having helped to make the present study possible. The re-

search and writings of his teacher and Chairman of the Super-

visory Committee, T. Lynn Smith, Graduate Research Professor,

Department of Sociology, University of Florida, have provided

the basic frame of reference and many of the methods employed

in the present treatise. The writer is also very grateful

for numerous hours of counsel and guidance offered to him by

Dr. Smith in the preparation of this manuscript. Dr. Smith's

knowledge and experience in the fields of demography and the

study of Latin American societies have contributed greatly to

the writer's understanding of these areas.

Gratitude is expressed to other members of the Super-

visory Committee for their instruction and sympathetic under-

standing throughout the process of graduate study and for

their interest and assistance in the presentation of the

dissertation. These members are Gerald R. Leslie, Professor

of Sociology and Chairman of the department, John V. D.

Saunders, Professor of Sociology, Joseph S. Vandiver, Pro-

fessor of Sociology and Graduate Advisor, and Andres SuArez,

Professor of Latin American Studies, History, and Political

Science. The writer is also grateful to E. Wilbur Bock,

Associate Professor of Sociology, who graciously accepted to

substitute for Dr. Leslie during the defense of the disser-

tation when the latter could not be present.

Appreciation is expressed as well to Dr. Leslie, Dr.

Smith, and Dr. William E. Carter, Director of the Center for

Latin American Studies and Professor of Anthropology, who

helped to secure a graduate fellowship made possible by the

United States National Defense Education Act, which permitted

the writer to devote full time to graduate study.

While the research for the present study was being

conducted in Mexico, Licenciado Ruben Gleason Galicia,

Director General of the Bureau of Statistics of the Mexican

government, was particularly helpful in providing materials

and equipment for computations. Licenciado Radl Benitez

Zenteno, Director of the Instituto de Investigaciones

Sociales of the National Autonomous University of Mexico and

Codirector of the Centro de Estudios Economicos y DemogrAficos

of the Colegio de Mexico, graciously made office space and

computing equipment available for the research.

The writer also expresses gratitude to the following

persons: Drs. J. Winston Crawley and Charles W. Bryan, Direc-

tor of the Overseas Division and Secretary for Middle America

and the Caribbean, respectively, of the Foreign Mission

Board of the Southern Baptist Convention, for their assis-

tance and cooperation in permitting the writer to devote

considerable time to the completion of the manuscript, and

to Ms. Roberta Solt, who patiently and efficiently worked

with the writer while she typed the manuscript.

Finally, immeasurable gratitude is owed to my devoted

wife, Charlotte Martin Bridges, who did all of the preliminary

typing of the dissertation, made helpful suggestions, and pro-

vided constant love and encouragement. The writer is indebted

to his eldest daughter, Rebecca Ann, for her graphic prepara-

tion of the figures in the manuscript, and to his other

daughters, Deborah Lea and Esther Marelyn, who, not only

rendered assistance, but relinquished hours of time which

would have otherwise been spent with them.


Acknowledgments . .... iv

List of Tables . .... ix

List of Figures .. . .... xiii

Abstract . . .xv

J I Introduction .. ... ... .. .. 2
II Survey of the Literature . 9

SIII Number and Geographic Distribution
of the Inhabitants. . ... .22

IV Age Composition . .. 37
V Sex Composition . .. 64
'VI Rural or Urban Residence. . 85
VII Ethnic Composition and Nativity .. 101
VIII Religious Affiliations . .. 116
IX Marital Condition . .. 139
X Educational Status . .. 161
-'XI Occupational Status . ... 174

XII Fertility . .... 199
XIII Mortality . ... .. 219

SXIV Immigration and Emigration .. ... 247
XV Internal Migration. . ... 269

- XVI The Growth of Population .... .302
XVII Conclusions .................. 315

List of References . .. 334

Additional References .... ....... .343

Biographical Sketch . .. 345



I Population, Area, and Density of Population
for the Twenty-Five Most-Populous Countries
of the World: Latest Census and Midyear
Estimates for 1970 . .

II Population, Area, and Density of Population
for Latin American Countries and the United
States: Latest Census and Midyear Estimates
for 1970 . . .

III Number, Geographic Distribution, and Density
of the Population of Mexico, by Regions and
Major Civil Divisions, 1970 . .

IV Indexes Showing the Extent to Which Each Ma-
jor Civil Division Had More or Less Than Its
Pro Rata Share of the Population of Three
Broad Age Groups, 1970 . .

V Dependency Ratios and Indexes Showing the
Extent to Which Each Major Division Had
More or Less Than Its Pro Rata Share of
the Urban and Rural Population, 1970 .

VI The Reported Number of Males and Females
in Selected Age Groups in 1960 and 1970.

VII Sex Ratios in the Major Civil Divisions,
by Three Broad Age Groups, 1970 .

VIII Sex Ratios in the Major Civil Divisions,
by Residence, 1970 . .

IX Sex Ratios among the Rural and Urban
Populations in Mexico, 1921-70 .

X Numbers and Percentages of the Population
of Mexico Residing in Places of Stated
Size, 1970 and 1960 .. .

XI Populations of the Major Civil Divisions
of Mexico, Classified by Region and Resi-
dence, 1970 . .

. 24

. 27

. 29

. 54

. 89

S 94

* .

XII Country of Birth of the Foreign-Born
Population of Mexico, 1960 .

XIII Numbers and Percentages of the Popula-
tion, Aged Five and Over, in Three
Ethnic Groups, by Region and Civil
Division, 1970 . .

XIV Distribution of the Foreign-Born by
Civil Division, 1970 . .

XV Numbers and Proportions of Persons
Speaking Indigenous Languages in the
Population of Mexico, 1930-70 .

XVI Numbers and Proportions of Foreign-Born
in the Population of Mexico, 1910-70 .

XVII Proportions of the Population in the
Religious Categories, According to
Region and Civil Division, 1970 .

XVIII Proportions of the Population in the
Religious Categories, 1900-70 .

XIX Sex Ratios of the Population in the
Religious Categories, 1900-70 .

XX Proportions of the Population, Aged
Twelve and Over, According to Marital
Status and Rurality, by Civil Division,
1970 . . .

XXI Changes in the Marital Status of the
Population of Mexico, by Age and Sex,
1940-70 . .

SXXII Proportions of Illiterates among Per-
sons Ten Years of Age and Over, by Age
and Sex, 1970 . .

XXIII The Proportions of the Population That
Are Illiterate, That Live in Rural
Localities, and That Speak Only Indi-
genous Languages, by Civil Divisions,
1970 . . .

XXIV Population Ten Years of Age and Over,
Literate and Illiterate, by Sex,
1910-70 . .

. .. 103

* 110

. 114

* 115

. 123

* 129

. 135

. 141

* 159

. 166 .1

. 168

. 172

. .

XXV Numbers and Proportions of the Population
Employed in Each of the Major Industry
Groups in Mexico, by Sex, 1970 .. .

XXVI Relative Importance of Three Major In-
dustry Groups in Providing Work for the
Economically Active Population of Mexico,
by Regions and Civil Divisions, 1970 .. 191

XXVII Numbers and Proportions of the Economi-
cally Active Population of Mexico, by
Sex, 1950-70 . . 195

XXVIII Numbers and Proportions of the Population
Employed in Each of the Major Industry
Groups in Mexico, 1950-70 . .96

XXIX Fertility Ratios and Crude Birth Rates
for Countries of Latin America and
Selected Developed Nations, by Latest
Year for Which Reliable Data Are
Available . . .204

XXX The Major Civil Divisions of Mexico
Ranked According to the Fertility
Ratios of Their Populations and Pro-
portions of the Population Classified
as Rural, 1970 . .... 207

XXXI The Most Rural Major Civil Divisions of
Mexico, Arrayed According to the Level
of Rurality and Ranked According to the
Fertility Ratios of Their Populations
and the Proportions of the Populations
Which Spoke No Spanish, 1970 .... .... 211

XXXII Fertility Ratios of the Rural and Urban
Populations of Mexico, by Selected Civil
Divisions, 1970 . .... 213

,XXXIII Crude Death Rates and Infant Mortality
Rates for Countries of Latin America
and Selected Developed Nations, by
Latest Year for Which Reliable Data
Are Available . .... 224

SXXXIV Reported Crude Death Rates and Infant
Mortality Rates, by Region and Major
Civil Division, 1970 . .... 228

XXXV Crude Death Rates, by Age and Sex, 1970 .

SXXXVI Changes in the Expectation of Life of
the Population of Mexico, 1930, 1940,
1950, 1959-61, and 1965-70, by Selected
Ages and by Sex . .

XXXVII Specific Death Rates for Selected Causes,
1932, 1952, and 1970 . .


Immigration and Emigration, Mexico,
1911-69 . . .

. 233

. 241

. 250

XXXIX Nationality of Immigrants to Mexico,
1928-69 . ... .. .256

XL Migrants from Various Civil Divisions
Who Moved to the Distrito Federal on
Their Last Migration, 1960-70 ... 275

XLI Gains and Losses by Major Civil Divisions
Due to Migration in Mexico, 1960-70 .. 279

XLII Exchange of Migrants on Their Last Migra-
tion between Mexican Civil Divisions,
1960-70, Based on 1970 Census Data Show-
ing Civil Division of Origin and Resi-
dence . .... ..... 284

XLIII The Absolute and Relative Importance of
Internal Migrations in Mexico, According
to Place of Birth and Residence, 1921-70 293

XLIV Estimates of Net Migration in Mexico, by
Major Civil Divisions, 1940-70 ... .295

p XLV The Growth of Population in Mexico, 1795-
1970 . . 304

SXLVI The Growth of Population in Mexico, 1900-
60 and 1960-70, by Major Civil Divisions 307 -

. 231


1 The Major Civil Divisions of Mexico ...... 32

2 A Comparison of the Age-Sex Pyramid
for Mexico and the United States, 1970 .

3 Age-Sex Pyramid for the Rural and
Urban Populations of Mexico, 1970 .

4 Index Numbers Showing the Relative
Importance of Each Age Group in the
Rural and Urban Populations of Mexico,
by Sex, 1970. . . 50

5 Changes in the Proportions of People
in Three Broad Age Groups by Sex,
Mexico, 1910-1970 . ... 62

6 Sex Ratios for Mexico, by Age, 1970 ...... 67

7 Changes in the Sex Ratios in Mexico
and the Distrito Federal, 1900-1970 ...... 82

8 The Growth of Population in Mexico,
1921-1970 . . .(

9 The Relationship of Age to Marital
Status among the Population of Mexico,
1970 . . .. .148

10 Marital Status of the Male Populations
of Mexico and the United States, by
Age, 1970 . . .. .152

11 Marital Status of the Female Popula-
tions of Mexico and the United States,
by Age, 1970. . .. .153

12 Percentages of the Populations of the
Distrito Federal and Chiapas in the
Labor Force, by Age and Sex, 1970 ..... .178


13 Trends in the Number of Children under
Five per 100 Women Aged Fifteen to
Forty-Four in Mexico, 1921-1970 .

14 Variations in the Reported Crude Birth
Rates of Selected Countries, 1935-1970

15 Trends in the Infant-Mortality Rate in
Mexico, by Sex, 1936-1970 .

16 The Principal Nationalities Represented
Among the Immigrants to Mexico, 1928-
1967 . . .

17 The Growth of Population During the
Twentieth Century in Mexico, Brazil,
Spain, and the United States .

18 The Growth of Population Between 1900
and 1970 in Mexico's Most Populous
Civil Divisions . .


. 215

. 217

. 237

* 258

. 306



Abstract of Dissertation Presented to the Graduate Council
of the University of Florida in Partial Fulfillment
of the Requirements for the Degree of Doctor of Philosophy



Julian C. Bridges
December 1973

Chairman: Dr. T. Lynn Smith
Major Department: Sociology

This study is an analysis of the basic characteristics

and trends regarding the population of Mexico. The analysis

includes consideration of all the principal aspects of demogra-

phy, namely, the number and geographic distribution of the in-

habitants, composition, or characteristics, of the population,

the vital processes, migration, and growth of the population.

Various methods, well-known in the field of demography, are

utilized throughout the study. Frequently, features of the

population of Mexico are compared with those of other countries

in Latin America or other parts of the world.

Primary attention is given in each chapter to an analy-

sis of the 1970 materials, and a concluding section compares

these findings with those of previous years. Use is made of

all census materials beginning with the first enumeration in

1895. Data on vital statistics and migrations are also

evaluated and analyzed from the time that these materials

first became available until 1970. Particular attention is

given to changes and trends which occurred between 1960 and


The nation of Mexico as a whole and its thirty-two

major civil divisions constitute the geographic area under

consideration in the study. All of the forty-six tables and

eighteen figures used in the manuscript are original and in-

clude the latest data available at the time of writing. The

specific characteristics of Mexico's population, to each of

which an entire chapter is dedicated, are age, sex, rural

or urban residence, ethnic composition and nativity, religious

affiliations, marital condition, levels of education, and

occupational status. Other chapters each deal with fertility,

mortality, immigration and emigration, and internal migration.

Fifty-nine conclusions are drawn, among which are the


In 1970 the population of Mexico constituted approxi-

mately 28 percent of all the people who inhabit the eighteen

countries of Spanish America.

Mexico's population is very unevenly distributed

among the major civil divisions. The four most-populous

divisions--Distrito Federal (the national capital), the state

of Mexico, Veracruz, and Jalisco--all are located in the cen-

tral part of the republic and, in 1970, contained 37 percent

of the country's total population, while they comprise


only 9 percent of the national territory.

Only 50.2 percent of Mexico's inhabitants were in

the economically productive category of ages 15-64 in

1970, while 46.2 percent were less than age 15 and 3.6 per-

cent were aged 65 and over.

In spite of extraordinary migration from the country-

side to the cities in recent decades, in 1970 almost two-

thirds of the nation's population still resided in population

nuclei of less than 20,000 people.

From 1960 to 1970 there was a substantial increase

in the number and proportion of persons in the population

who were literate and of school-age children who were enrolled

in classes. However, due to the extraordinary growth in

population, there were almost as many illiterates and more

children not in school in 1970 than in 1960.

Mexico's actual birth rate in 1970 was estimated by

the writer to be about forty-four, while the death rate was

estimated to be about ten. Both will probably decline

slowly in the 1970's.

Over one-fourth of all native-born migrants who made

their last move to another civil division from 1960 to 1970

transferred their place of residence to the Distrito Federal,

and another one-fifth moved to the contiguous state of


Over the period 1921-70, Mexico had the highest

average annual rate of population increase of any of the


most-populous nations in the world. From 1960 to 1970 the

average rate of growth was 3.4 percent per annum.






This study is an analysis of the basic characteris-

tics and trends regarding the population of Mexico. The

analysis includes consideration of all the principal aspects

of demography, namely, the number and geographic distribu-

tion of the inhabitants, characteristics, or composition, of

the population, the vital processes, migration, and growth

of the population. Various methods, well-known in the field

of demography, are utilized throughout the study. Frequent-

ly, features of the population of Mexico are compared with

those of other countries in Latin America or other parts of

the world.


The general objective of the present study is to pre-

sent a demographic analysis of the people of Mexico. Con-

sequently, the overwhelming proportion of space is devoted

to the presentation of data and analyses of the numbers,

distribution, composition, and changes in the population

and to the factors which influence these components. More

specifically, this study seeks (1) to determine the essen-

tial features of Mexico's population, (2) to discern and

distinguish the changes occurring within it, and (3) to

identify and indicate some of the primary factors involved

in the population trends of the country. Primary attention

is given in each chapter to an analysis of the 1970 materials,

but a concluding section compares these findings with those

of previous years. In this manner changes and trends are



The nation of Mexico as a whole and its thirty-two

major civil divisions (twenty-nine states, two territories,

and a federal district) constitute the geographic area under

consideration in the present study. Unfortunately, at the

time of writing, 1970 census materials were not yet published

on the smaller administrative and political subdivisions

known as municipios. Thus, it was not possible to analyze

the population of these county-like entities in the present


The majority of the materials utilized in the pre-

sent research were derived from data in the general summary

of the ninth general census of population [1] conducted on

28 January 1970. However, some use is made of materials

from the first census of 1895, and from all the decennial

censuses beginning in 1900; comparisons are made whenever

data are available. Particular attention is given to

changes and trends which have occurred from 1960 to 1970.

Sources of Data

The data utilized in the present study have been

taken primarily from three sources, (1) the general census

of population usually conducted every ten years by the

Mexican Bureau of Statistics or its predecessor organiza-

tions, (2) the registrations of births, deaths, and migra-

tions also supervised by the Bureau of Statistics and

published annually or biennially in the series known as

Anuario estadistico, and (3) the various editions of the

Demographic Yearbook, published under the direction of the

Statistical Office of the United Nations.

Other materials are used throughout the treatise,

and references to these are indicated at the appropriate

places. Numerous works, particularly those on demography,

were consulted to develop the theoretical frame of reference

and the techniques employed in the pages which follow [2;

3; 4].

All of the tables, graphs, charts, and diagrams in

this manuscript were prepared by the writer. In no case

were all the data simply copied from other compilations.

Some computation was realized in the assembling of all

figures and tables, and in many cases all the calculations

contained therein are original.

A final source from which the writer draws occasion-

ally to make inferences is twelve years of experience with

Latin Americans, most of which has been obtained by living

in Mexico and traveling in most of the thirty-two civil di-


Evaluation of the Data

Since the 1970 census of population was the ninth

such official enumeration, considerable experience had been

gained by the Mexican Bureau of Statistics in obtaining such

information. Nevertheless, the writer has estimated that

there was a 3.0 percent underenumeration for both sexes in

the total census count.* There was no evidence that the

1970 census materials had been padded or inflated. The

registration of births in Mexico as a whole in 1970 was

estimated to be reasonably complete (at least 90 percent),

although the reporting of infant deaths is notably incom-

plete in remote regions of the more highly rural major

civil divisions [7].

Censuses taken before 1930 are considerably more un-

reliable than those after this year, and, particularly,

this is true of the enumeration in 1921, which has been

estimated by one of Mexico's leading demographers, Gilberto

Loyo, to be about 500,000, or 3.4 percent, short [8(1969):23].

*The writer used the technique of computing averages
for the number of reported births and deaths over three-year
periods [5:1-8] and the simplified form of the indirect
balancing equation method (since recorded migration from
1960 to 1970 was negligible) discussed in [6(1962):7-8].

The 1960 census also was estimated to be underenumerated

3.0 percent.


The nature of the population data makes it necessary

to employ highly sophisticated methods to obtain the desired

analyses. Usually nominal and ordinal measures which in-

volve simple, direct, and conventional procedures for

analyzing quantitative data are utilized. Since the census

and registration materials involve the use of large numbers,

there is little opportunity for variations greater than a

few tenths of a percentage point to be the result of chance.

Therefore, complicated analyses of difference that might

arise from sampling procedures are not necessary.

It is also possible, in most cases, to subsort the

compilations made by those agencies which publish the data

in such a way as to make direct comparisons according to

age, sex, rural and urban residence, and sometimes other

characteristics. This obviates the need to use correlation

analysis as a substitute for direct cross-tabulation. Thus,

the basic devices used to present the findings of the study

are percentages, ratios, proportions, index numbers, rates,

detailed tables, and graphic presentations of various types.

Significance of the Study

A demographic analysis of the population of Mexico

is important for several reasons. First, such an analysis

organizes the huge mass of data into a form where it can be

more easily understood and interpreted. As a result, in-

ferences can be drawn and applied to the areas of agricul-

ture, industry, education, employment and unemployment,

family life, religion, health, and so forth. Second, the

population of Mexico has many characteristics common to

other countries of the Third World and particularly to those

in Latin America. Thus, important comparisons and contrasts

can be made with the populations of other nations, both

those in development and those considered already to be

highly developed. Third, the present study is the most

complete analysis of Mexico's population as a whole yet

undertaken and, when compared with the results of all

previous censuses, can provide valuable insight into impor-

tant long-range trends and changes which the country is

undergoing. Finally, since this treatise utilizes tested

techniques in demography, it adds empirically verified

knowledge to the general field of population study.

Order of Procedure

The plan of presentation followed above in outlining

the field of demography is followed closely throughout the

study. Before beginning the discussion of the number and

geographic distribution of the inhabitants of Mexico, which

constitutes Part Two and Chapter III, a second introductory

chapter is included to present the reader with a review of

the most important literature bearing on the general and

specific topic under study.

Part Three of the presentation deals with the compo-

sition, or characteristics, of Mexico's population and dis-

cusses age, sex, rural or urban residence, marital condition,

religious affiliations, ethnic composition and nativity,

levels of education, and occupational status. The next sec-

tion, Part Four, discusses the vital processes, fertility

and mortality, while Part Five includes immigration and emi-

gration as well as internal migration. A final division of

the study, Part Six, presents the vital topic of growth of

the population and is followed by a brief section of con-




Interest in matters related to population has existed

since the earliest recorded history, but attempts at objec-

tivity in seeking to determine demographic relationships,

principles, and trends date from relatively recent times.

Therefore, while concern and speculation about population

have been engaged in by politicians and other national

leaders throughout history, there is no evidence to indicate

that they had any theoretical interest in the subject or

practiced the systematizing of their knowledge in order to

draw inferences as is done in the science of demography. It

is the purpose of this chapter to indicate and describe

briefly the major works and landmarks in the development of

demography, in general,* and of demographic analysis and

the study of Mexico's population, in particular.

Graunt: The Scientific Study of Population

An Englishman, John Graunt, can be credited with

*For this portion of the chapter, the present writer
generally follows an outline set out in [3:19-38; 9:8-37].

publishing the first genuinely scientific investigation of

population. His contributions appeared in Natural and Poli-

tical Observations Mentioned in the Following Index and Made

upon the Bills of Mortality by John Graunt [10], in 1662.

Utilizing the records of burial permits issued in greater Lon-

don for the years 1604 to 1661, Graunt compared these data with

those on births taken from parish registers of christenings.

He also secured information on causes of death and the sex of

the persons involved. By carefully assembling the data into

statistical tables and using the method of induction,

Graunt was able to arrive at 106 observations on the nature

of population. Many of these generalizations have been,

and continue to be, verified by students of demography in

their independent inquiries. Graunt's propositions dealt

particularly with patterns of migration and with fertility

and mortality differentials between rural and urban areas.

Malthus: Growth of Population

In the late 1700's the rapid increase in human popu-

lation generated considerable concern about how this might

affect national economies. Thomas R. Malthus set forth the

idea that population growth would ultimately surpass the

sufficient food supply in his Essay on Population [11]. Mal-

thus argued that population tends to grow by geometric pro-

portions, while the means of subsistence increases only at

-an arithmetic rate. On the basis of this rather obvious

fact, Malthus then deduced a number of propositions which

imply a pessimistic future for the human race.

Unfortunately, some of Malthus' generalizations

have influenced a sizable number of persons to assume that

long-time trends in the birth rate can be predicted with a

high degree of accuracy. This has contributed to the be-

lief that population projections may be made with relia-

bility far into the future. Such forecasts often are, not

only grossly in error, but time consuming, thus diverting

attention from other needed demographic research. Never-

theless, the influence of Malthusian thinking has made such

an impact on society in general that his writings cannot

legitimately be excluded from a serious consideration of

the historical development of demography.

DeBow: Population Composition

J. D. B. DeBow is responsible for revolutionizing

the use of the data of the United States Census of 1850,

particularly those materials which deal with the character-

istics of the population. The procedures he instituted for

the handling of census materials have enabled contemporary

demographers to make comparisons of many population charac-

teristics back to that year, 1850. DeBow, Superintendent

of the United States Census less than two years, had intro-

duced the idea of obtaining valuable information on popula-

tion composition when he served as organizer and director

of a state bureau of statistics in Louisiana. There he

obtained and published in a periodical he founded, DeBow's

Review, valuable data on the age, sex, race, national ori-

gin, residence, fertility, occupational condition, marital

status of the inhabitants, mortality, migration, and growth

of the state's population.

On the basis of this experience, DeBow compiled and

published information on many of the same subjects in his

Statistical View of the United States [12], based on the

census of 1850. This work became another landmark in the

development of the field of demography.

Qudtlet and Heuschling: International
Population Statistics

The first comprehensive summary of population data

for most of those countries which had instituted and begun

to refine their censuses was published in 1866 as Statisque

international du movement de la population [13],* by two

Belgian statisticians, Adolph Qu4telet and Xavier Heuschling.

These men also succeeded in leading officials from the

various nations to agree upon and adopt a common statistical

set of forms to use in their respective countries.

Subsequently, other international compilations of

population data were made by the French Ministere du Tra-

*Cited by [3:27].

vail et de la Prevoyance Social, the International Insti-

tute of Statistics at the Hague [14],* and the League of

Nations [15].* After World War II the task of compiling

and publishing international population data was assumed by

the United Nations, which issued, in 1949, the Demographic

Yearbook (1948) [6] and has continued publishing this

annually ever since, although in 1951 the yearbook contained

data for the years 1949-50.*

Wilcox and Thompson: The Fertility Ratio

For many years the students of population had

grappled with the problem of how to arrive at a reasonably

reliable measure of fertility. The registration of births

was often far from complete in most countries of the world,

so the computation of an index which depended upon such

data was almost useless. Walter F. Wilcox, as early as

1911, presented before scholars what has come to be known

as the fertility ratio (sometimes called the child-woman

ratio), which is computed from census data alone. The

ratio is simply the number of children aged 0-4 to the num-

ber of women of childbearing age, 15-44, 15-49, or 20-49,

multiplied by a constant of 100 or 1,000.

While Wilcox first introduced the fertility ratio,

it was his student Warren S. Thompson who popularized it by

*Cited by [3:27].

employing the ratio to measure fertility from the United

States Census of 1920 and publishing the results [16]. The

ratio has since been used widely by demographers to measure

the rate of reproduction, particularly in those areas of

the world where birth statistics are not yet reliable.

Smith: State Population Analysis

As early as 1937 T. Lynn Smith introduced valuable

techniques for analyzing a population according to the num-

ber and distribution of its inhabitants, its characteristics

and changes, and its growth [17]. His methods were enlarged

and expanded in his later works [18; 19; 20; 3]. The frame

of reference employed by Smith has since been used and

adapted widely by other demographers.

Some examples of the more important studies on the

populations of the various United States, listed in chrono-

logical order by date of publication, are those by Petty

[21], Hawley [22], Knox [23], Thompson [24], Anderson [25],

Bertrand [26], Skrabanek [27], Zopf [4], and Lind [28].

National Population Studies

A number of demographers have undertaken analyses

of national populations, and it is worthwhile to note some

of the more prominent. Again, among the first to use

methods of demographic analysis in the study of the entire

population of a nation was T. Lynn Smith, who first published

the results of his research on Brazil in 1946 [2]. Similar

demographic techniques were employed by Whetten in his

volumes on Mexico and, later, on Guatemala [29; 30], Taylor

on Argentina [31], and Nelson on Cuba [32], though these

works were not devoted to the study of population alone.

Lorimer [33] also published about this time a significant

analysis of the people of the U.S.S.R.

Since 1950 there have been a considerable number of

national studies of population, most of which employ methods

of analysis very similar to those utilized in the present

study. One of the most thorough analyses was that supervised

by Davis [34] on India and Pakistan. This extensive work

pursues all aspects of the populations studied, from number

and distribution of the inhabitants to growth of the popula-

tion, including the characteristics of and changes among

the peoples involved. Other national studies which followed

soon thereafter are those by Mayer [35], Lawrence [36],

Wynne [37], and Mauldin and Akers [38].

Based on the 1950 Census of the Americas, conducted

simultaneously for the first time by most of the Latin Ameri-

can countries (another major landmark in the development

of demography), Saunders [39] published what was probably

the first entire volume devoted to the population analysis

of a country in Latin America. The U.S. Bureau of the Cen-

sus continued to sponsor population studies of various

countries of the world, and these analyses were accomplished

by Meyers and Mauldin [40], Meyers and Campbell [41], Siegel

[42], and Wynne [43]. In 1957 Roberts [44] published the

first demographic study on a single country or territory in

the Caribbean. The last two years of the decade also saw the

publication of three very significant national demographic

analyses, Irene Taeuber's study [45] of the population of

Japan, her collaboration with Conrad Taeuber [46] on popula-

tion changes in the United States, and Donald Bogue's very

extensive analysis [47] of the United States population.

In the decade of the sixties, national population

studies were conducted in numerous parts of the world,

particularly among countries in development. Some of the

most important of these demographic investigations are

those conducted by Smith [5], Aird [48], Brass et al. [49],

Jones [50], Yabour de Caldera [51], and Nitisastro [52].

Finally, a monograph by Hathaway et al. [53] on the rural

population of the United States can be mentioned as an

excellent example of a relatively recent study which em-

ploys extensively the techniques of demographic analysis.

Demographic Research on Mexico

The basis for gathering statistical data on a na-

tional scale in Mexico can be considered to have begun in

1867 when the civil registry, Registro Civil, was first

established. In 1882 the registry came under the supervi-

sion of the Mexican Bureau of Statistics, Direcci6n General

de Estadistica, which was founded the same year. The first

issue of the Bureau's statistical yearbook, Anuario estadfs-

tico was published in 1894, and the Boletfn demografico de

la Repdblica Mexicana was begun only two years later. Dr.

Antonio Peiafiel, Director General of the Bureau of Statis-

tics, also organized and supervised the country's first

general census of population in 1895.

Both the Anuario and the Boletin demografico had to

be discontinued during the years just preceding the Mexican

revolution, 1910-17, but in 1925 the Bureau of Statistics

was again able to begin publishing compendia of statistical

information on Mexico. By 1930 when the country's fifth

general census was conducted, a vast storehouse of valuable

information was being compiled in the decennial enumera-

tions and, during the 1930's, statistics on births and

deaths, while still incomplete, became much more reliable

than before. Nevertheless, before 1940 there was little in-

terest in demographic studies, and what was published was

more of an anthropological and historical nature [54; 55:9].

It is worthwhile to mention one Mexican scholar,

however, who was a dedicated student of demography even as

early as the 1930's. Gilberto Loyo, whose name has been

associated with statistical and economic investigation in

Mexico for several decades, was publishing his treatises

on aspects of the population of Mexico throughout the decade

before 1940.*

In 1943 the first Interamerican Demographic Congress

was held in Mexico. This meeting stressed the importance of

studying the relation between population tendencies and

trends to social and economic aspects of development [59;

55:10]. Undoubtedly, this Congress helped to motivate

Mexican scholars to devote more time to strictly demographic

investigation, and the results have been several studies by

Gilberto Loyo and Julio Dur6n Ochoa [60; 61; 62; 63]. While

none of these were extensive analyses of the entire popula-

tion, they have made valuable contributions to the growing

quantity of literature on Mexican demography. Duran Ochoa,

however, did publish, in 1955, a rather complete analysis

of Mexico's population, based primarily on data from the

1940 and 1950 censuses [64].

Various institutions have contributed to demographic

investigation in Mexico. The Instituto de Investigaciones

Sociales of the National Autonomous University of Mexico,

founded in 1933 and reorganized in 1938 under the direction

of Dr. Lucio Mendieta y Nuiez, has published various speci-

fic studies on population in its journal Revista mexicana

*Examples of Loyo's writings pertaining to demogra-
phy, though not strictly analytical in nature,were [56; 57
58]. See also [55:9].

de sociologfa* and one work exclusively on the subject of

population analysis written by the current director of the

institute, Raul Benftez Zenteno [66]. The Instituto has

also conducted sample surveys on fertility and other aspects

of population study.

The Centro Latinoamericano de Demografia (CELADE),

situated in Santiago de Chile and founded in 1958 under the

sponsorship of the United Nations, has also contributed to

demographic research in Mexico by placing its findings at

the disposition of the federal government and of other in-

stitutions in Mexico [67; 68].

In 1964 the Centro de Estudios Economicos y Demogrd-

ficos of the Colegio de Mexico was established for the pri-

mary purpose of increasing the body of knowledge in demogra-

phy and economics, particularly as it relates to economic

and social development. The Centro trains students from

throughout Latin America, primarily at the postgraduate

level. The Centro, under the direction of Raul Benitez

Zenteno and Gustavo Cabrera Acevedo who were trained at

CELADE, also established a scientific journal in the fall

of 1967, Demograffa y economfa. Since its founding this

quarterly journal has been dedicated to the dissemination

of information on scholarly subjects related to demography,

particularly those pertaining to Mexico and the remainder

*An example of one of the many demographic studies
published is [65].


of Latin America. In 1970 the Centro sponsored the publica-

tion of a composite work of its investigators, which has

made a genuine contribution to the field of demography [69].





The present analysis of Mexico's population commences

with a study of the number and geographic distribution of the

inhabitants as of 1970. This was dictated by the fact that

the number of inhabitants and the way they are geographically

distributed throughout a specified area are the most impor-

tant features of population study. These aspects are of in-

trinsic value in that often the first evaluations of a na-

tion, or other political unit, are made on the basis of the

size of its population and the number of persons living in

a given unit of area.

In contemporary society the essentials about the num-

ber and distribution of a nation's inhabitants also frequent-

ly are needed for purposes of research and administration.

For example, sociologists need these data before they can

compute indexes of criminality, juvenile delinquency, and

marriage. Economists must have them before they can calcu-

late the ratios which are utilized in their analyses. Demo-

graphers themselves must use the counts or estimates of the

number of persons in a given population or segment of it if

they are to analyze fertility, mortality, and the expectation

-of life [3:41-42].

Administrators must know the size of a population

and where the inhabitants are located spatially in order to

make plans for the present and the future. An administra-

tive or political unit may have too many or too few people

for the unit's natural and industrial resources. In other

words, the material level of living of the inhabitants is

inseparably linked to their number and distribution. For

example, in order to realize the agricultural and industrial

potential of a nation, a ready supply of labor must be

available for the enterprises attempted in a given area.

Government or private planners find facts on the number and

spatial arrangement of the inhabitants of an area indispen-

sible to the decisions of whether or not to build or expand

housing developments, schools, hospitals, churches, or

business establishments [19:6].

Mexico's Relative Position

In the census taken on 28 January 1970, the number

of inhabitants enumerated in Mexico was 48,225,238 [1:3].

In the list of the most-populous countries of the world,

Mexico ranks rather high.

Table I contains a list of the twenty-five most-

populous nations of the world, according to the 1970 midyear

population estimates made by the United Nations. Of the more

than 210 countries and territories considered, Mexico ranked

thirteenth in the number of inhabitants living within its

national boundaries.

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7 million in the Distrito Federal, which alone accounted

for over 14 percent of the nation's total population.

The four most-populous civil divisions (Distrito

Federal, M4xico, Veracruz, and Jalisco, each with more than

3 million people) have 37 percent of the country's total

number of inhabitants, while they include only 9 percent of

the nation's territory. In Table III the civil divisions

have been grouped into geographical regions. It should be

noted that all of the seven most-populous divisions are

located in the central part of the republic, where the cli-

mate is generally more moderate and where much larger con-

centrations of fertile land are found than in the arid

regions of the north and north central parts of Mexico, which

are characterized by extreme temperatures.

The four least-populous civil divisions (Campeche,

Colima, and the territories of Baja California and Quintana

Roo) together contain only 1.5 percent of Mexico's total

population, although they include 9 percent of the country's

total territory.

In 1970, for the first time in Mexican history,

more than half of the country's thirty-two divisions had

over 1 million inhabitants, while only fourteen of the enti-

ties had populations of less than 1 million.

The density of population also varied enormously

among the civil divisions of Mexico, thus reflecting the

very uneven distribution of the nation's people. Although

the national average of number of persons per square kilo-

meter is only 24.5, the Federal District has an extremely

high concentration index of 4,585.8 persons for each square

kilometer of area. In stark contrast the territories of

Baja California and Quintana Roo had fewer than two persons

per square kilometer. The four largest states in Mexico,

in area (Chihuahua, Sonora, Coahuila, and Durango), each

located in the arid north of the country, had a density of

no more than 7.8 persons per square kilometer. This is

particularly noteworthy in that all four states contain

sizable urban centers. In other words, if the inhabitants

living in these centers were subtracted from the total num-

ber of inhabitants in each state, the density for the divi-

sions would be very much lower. Another way of stating this

is that almost no inhabitants live on the thousands of

square kilometers of dry, dusty land in this part of the re-


With the exception of Nayarit, which borders on the

largely arid north, all of the major civil divisions in the

central region rank with those having the highest density

of population in the nation. In fact, 58 percent of the

country's inhabitants live in these thirteen entities, which

include only 18 percent of the national territory.

It should be noted that the civil division with the

second-highest density of the nation, the state of M4xico,

with 178.6 persons per square kilometer, borders the Distrito


Federal on three sides. The index for this state was only

88.4 at the time of the census in 1960 [70:1]. As might be

expected, this radical change in density is due primarily

to the urban sprawl of persons who work in the Distrito

Federal, but reside in the neighboring state of Mexico.





Few features of Mexico's population are of greater

significance than the manner in which it is distributed

according to age. For at least three reasons an adequate

study of the age distribution is basic to almost all popu-

lation analyses [3:151-52].

First, age is one of the most important characteris-

tics of the individual. The way he thinks and behaves as

well as his needs are all closely related to the number of

years he has lived. Age affects such diverse matters as his

occupation, his tendency or ability to migrate, his oppor-

tunities for parenthood, and even his survival [20:148-49].

Second, the age profile is a fundamental feature of

the entire society. This is true because the absolute and

relative importance of the different age groups are very

closely associated with social and economic factors in the

society. Among the most obvious uses of age data are those

related to the planning of military activities, educational

facilities, medical institutions, and other programs of

social welfare. Also, many private organizations, such as

large companies and the entire life-insurance business, are

vitally interested in obtaining accurate, reliable data on

the age distribution of the population.

The proportion of persons in the productive age

ranges (15-64) of a society is a vital factor in determining

its ability to finance social programs and services for

those persons in the nonproductive age categories (those

under 15 and 65 and over).

Finally, a proper study of the age distribution of

a population is essential, because allowances or correc-

tions for the age factor must be made if the data available

are to be reliable. Since the age factor is so closely

related to the birth, mortality, and marriage rates, and to

the incidence of migration, if age is not corrected for,

adequate analyses and comparisons involving these phenomena

will have little legitimate significance.

The Reliability of Age Data

In any census enumeration certain inaccuracies

occur in the gathering of the age data. For example, respon-

dents tend to round off their ages and report numbers which

end with zero. This is particularly true for persons who

have reached middle age. Only slightly less pronounced is

the tendency for persons to report their age as ending in

the number five, particularly from age forty-five and on.

Even numbers such as thirty-six or forty-two, for example,

tend to be considerably more popular in age distributions

than are the odd numbers. Elderly people tend to add a few

years to their age, and, for some strange reason, children

under one year of age are often missed by census enumerators.

As a nation gains experience in conducting its cen-

sus and as the educational level of the population is lifted,

all of the errors of reporting information on the age of

respondents decrease, but they do not disappear entirely.

For this reason, Smith has devised the following method for

evaluating the extent to which ages are reported correctly:

Take the distribution of ages by single years,
from under one to ninety-nine, which most
modern censuses publish, and ignore the very
few who have passed their hundredth birthdays
or whose ages are unreported. If all of the
ages were known and reported correctly, al-
most exactly 10 percent of the total should
be in the first year of age and the others
ending with zero, another 10 percent in the
other ages exactly divisible by five, 40 per-
cent in other even-number ages, and the re-
maining 40 percent in the odd-numbers not
divisible exactly by five. Thus all of the
tendencies to concentrate mentioned above
should reduce the percentages in the last of
these four categories. Consequently, by com-
paring the total number of persons reported
in the age groups one, three, seven, nine,
eleven, thirteen, .ninety-three, ninety-
seven, and ninety-nine, with the figure
corresponding to 40 percent of the total,
one may secure an indicator of the relia-
bility with which the ages have been reported.
Perfect reporting would produce a score of
100, whereas any concentration of the ages
ending in zero, five, or the other even num-
bers would produce an index of less than 100.
The greater the error, the smaller the score.

The score for the total population of Mexico in 1960

was 81.5, indicating a considerable amount of error in the

age data. The percentage of illiteracy among these people

aged ten and over was 33.5 percent in 1960.* By 1970 sub-

stantial improvement had been made in the accuracy of age

reporting. The score for the nation's total population was

87.5, and the percentage of illiteracy had decreased to

23.7 percent.** This improved educational status of the

population, the government's long experience in census taking,

and some efforts in large cities to allow respondents them-

selves to complete the census questionnaire are probably re-

sponsible for reducing the margin of error in age reporting

and in other items of the 1970 census inventory.

In 1970 males scored 88.6 in the accuracy of age

data. This was slightly higher than the score for females,

86.4. The Federal District, in which only 9.1 percent of

the population was illiterate in 1970, had a score for age

reporting of 92.5. The score for males was 94.1 and for

females, 91.2. In contrast, the state of Chiapas, which had

the nation's highest proportion of illiterates, 43.3 per-

cent, had a score of only 77.1 for the accuracy of its age

data in 1970. The scores for males in the state was 79.0

*Score computed from data in [6(1962):204]. Percen-
tage of illiteracy calculated from data in [6(1963):344].

S **Computed from data in [1:11, 85].

and, for females, 74.9.* The above scores support the

assumption that age reporting will be more accurate in

areas which have a higher level of education among their

population and that scores for males will be slightly

higher than those for females.

Factors Affecting Age Distribution

The primary factors which are responsible for the

general configuration of any age distribution in a popula-

tion are the three demographic processes, fertility, mortality,

and migration. When these three processes are appreciably

influenced by secondary factors such as wars and epidemics,

it is well to take them into consideration also.

Birth rates and death rates usually act together to

influence the age distribution. For'example, when fertility

is high and mortality is low or declining, a high propor-

tion of the population will consist of children. Likewise,

the population will be dynamic rather than relatively static

with respect to its growth. This is true since the number

of births is not countered by an approximately equal number

of deaths. Mexico currently has such a changing, rapidly

growing population.

The age-sex pyramid is a graphic representation

which portrays the absolute and/or relative numbers of males

*Computed from data in [1:11, 14-15, 85].

and females in the specific age groupings of a given popu-

lation. The pyramid reflects the societal history of the

population for almost a century. Sharp changes in the

birth rate, precipitous changes in the death rate, large

migrations, and such matters as wars and epidemics all

leave their scars on the pyramid.

Age and sex pyramids for Mexico and the United States

of America are compared in Figure 2. It can be noted imme-

diately that the pyramid for Mexico is squat in form and has

a very broad base. In contrast, the United States pyramid

is more elongated and pear-shaped. Neither is absolutely

symmetrical with respect to its center column, which obviously

indicates that males and females comprise differing propor-

tions of the population in almost every age category.

In 1970, 46.2 percent of Mexico's total population

was less than fifteen years of age compared with only 28.5

percent in the same category in the United States. Thus,

Mexico is faced with a great challenge to provide services

for this age group, which is very largely unproductive.

In Mexico 50.2 percent of the total population in

1970 was age fifteen to sixty-four, while the corresponding

proportion in the United States was 61.1 percent. This

means that approximately one-half of Mexico's inhabitants

must produce enough goods and services for the remainder of

the population.

Finally, it should be noted that only 3.6 percent of

9 8 7 6 5 4

Figure 2. A C

3 2 1


1 2 3 4 5 6 7 8 9

comparison of the Age-Sex Pyramid for Mexico and
United States, 1970

the people of Mexico were age sixty-five and over in 1970,

while 9.9 percent of the inhabitants of the United States

were in this age category. Thus, as yet Mexico can give

relatively little attention to providing services for the

elderly as compared to the needs of senior citizens in the

United States.

In other words, on a relative basis in the popula-

tion of Mexico, children are 162 percent as important, per-

sons in the productive age are 82 percent as important, and

those in the aged category are only 36 percent as important

as is the case in the population of the United States.

Since the 1930's, when fairly accurate reporting of

the number of births became available in Mexico, the birth

rate has been calculated to range between 41 and 46. Most

years it has hovered between 44 and 46 [6(1969):260-61;

6(1970):621]. During the same period, 1930-70, the death

rate dropped gradually from 25.6 to about 9.2 [6(1966):346-

47; 6(1970):655]. This reduction of deaths was due largely

to improved medical services in general and thus was spread

over many age groups and not only confined to a few of them

in the population. In addition, mortality is usually of

less significance than fertility in explaining population

changes. Therefore, since changes due to migrations, wars,

and epidemics have been negligible during the forty-year

period, the age-sex pyramid has remained relatively unchanged

in its basic shape, although the lowered death rate has con-

tributed to a gradually broadening base. It is interesting

to note that the last time the form of the age-sex pyramid

for the United States approximated the shape of the 1970

pyramid for Mexico was in 1850.*

One serious war and one epidemic did have an observable

effect on the form of Mexico's age-sex pyramid for 1970. From

1910 to 1917, the Mexican revolution, a bloody civil war, was

waged in the national territory. Also during this period a

world-wide epidemic of influenza swept across the country.

These two factors decimated the population of approximately

1.25 million persons [71:364]. For the only time in Mexican

censal history, there was a decrease in the total national

population. At the time of the census in 1921, there were

825,589 fewer persons reported to be in the population than

in the previous census of 1910.**

The deaths of combatants in time of war are largest

in the ages twenty to thirty. Since the revolution occurred

over fifty years before the time of the 1970 census, its

effects are not as easily detected on the most recent age-

sex pyramid. Nevertheless, the careful observer will note

that there is a rather marked decrease in the percent of

the population in the age groups of the pyramid beginning

with age seventy-five. The persons in this age category

*For a graphic comparison of the age-sex pyramid for
the United States in 1850 and that of Brazil in 1950, which
is very similar to the pyramid for Mexico in 1970, see [5].

**Computed from data in [72(1938):56-57].

and those immediately above it participated most actively

in the military aspects of the revolution. Age-sex pyramids

for previous censal years are not reproduced here, but they

reflect even more clearly the deaths which occurred during

the conflict.

The second principal effect of a serious war upon

the age distribution of a nation's population is the sharp

decline in the birth rate during the conflict. While

married men were away from their wives, the rate remained

low. Then, immediately after the termination of the war,

the birth rate rises sharply for a year or so to heights

considerably above those before the war and then falls again

to resume the prewar trend. The relatively small number of

babies born during the years of the war causes an indenta-

tion in the age-sex pyramid at the age groups which corres-

pond to the persons born during the conflict. In Figure 2

the relatively low percentages of age groups fifty to fifty-

four and fifty-five to fifty-nine are due to the low birth

rate during the revolution. It should be observed that age

groups thirty to thirty-four and thirty-five to thirty-nine

follow a very similar pattern in that they correspond to the

period in which those relatively few children born during

the revolution had themselves reached the age when their

children were born.

It can also be noted that the age categories forty-

five to forty-nine and twenty-five to twenty-nine are

unusually large since they represent the relatively high

number of births immediately following the revolution and

the correspondingly large birth rate twenty years later

when these persons reached the child-bearing period.

Large-scale migrations also affect the age distri-

bution of a population. The nature of the migration and

the distance traveled are the two principal factors which

determine the extent to which males and females of various

ages participate in the migrations [3:163]. For example,

most of those who migrate long distances, namely from one

country to another, are young adults and are predominantly

male. On the other hand, those who migrate to urban areas

from the surrounding countryside are largely female in sex

and are in their late teens and early twenties.

It is known that a sizable number of young adult

males, legally or illegally, cross the border into the United

States each year in search of employment. Although most of

these men eventually return to Mexico, this temporary emi-

gration from Mexico is one factor which can help to explain

the decidedly lower proportion of males than females in the

age groups from ages fifteen through twenty-nine. Also, it

is a known fact that women understate their ages, and this

would put many women who actually are ages thirty through

thirty-two into the under-thirty category.* No such thing

*A detailed study of this phenomenon is found in

is true for men.

Mexico has not permitted large-scale immigration

during the last 100 years. Thus, this factor has not

appreciably altered the shape of the age-sex pyramid for

the total population in 1970. Migration within the country

has been considerable, however, and this will be discussed

in the following section and in a later chapter.

Variations Within Mexico

Within Mexico there are many variations in the age

distributions, such as the differences between those for

persons living in the city and in the country and those

living in the different major civil divisions of the nation.

Rural-Urban Differences

Figure 3 has been prepared to show the differences

between the age profiles of urban and rural people. Figure

4 indicates the extent to which the two residence categories

contain more or less than their pro rata shares of persons

in each of the five-year age groupings. In the latter

figure, the proportion of the nation's population which falls

in each age group is made equivalent to 100, and the result-

ing computed index number shows the degree to which the per-

centage of those in the corresponding ages for a given resi-

dential group is above or below that proportion [4:39].

Careful observation of Figures 3 and 4 indicates


- S SS-




10 9 8 7 6 5 4 3 2 I I 2 3 4 5 6 7 8 9 10
Figure 3. Age-Sex Pyramid for the Rural and Urban
Populations of Mexico, 1970




















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that in 1970 the urban areas of Mexico were characterized

by nearly their pro rata share of both male and female

children under fifteen. The cities had a consistently

higher proportional share of the nation's population of

females from about age thirteen to the end of the life span.

Undoubtedly the primary factor in explaining this phenomenon

is that as soon as they enter their teens, many girls in

Mexico in rural areas migrate to the cities to attend more

advanced schools or find jobs as household servants and in

other occupations. Most of them never return to their for-

mer homes to live.

The urban districts were also characterized by a

slightly better-than-fair share of males aged sixteen to

fifty-seven and a gradually increasing underrepresentation

of them aged fifty-eight and over. Since a major trend

toward migration from rural to urban areas did not begin

until the 1940's in Mexico, men fifty-seven and over did not

participate in this migration and thus have continued to

live in rural districts.

Conversely, in 1970 rural areas had an overrepresen-

tation of both male and female children. This was due pri-

marily to the higher birth rate in agricultural districts

as compared to the cities. The rural areas have an under-

representation of males and females during most of their

productive ages. This pattern continues with respect to

females for the remainder of their life cycle, but there is

an overrepresentation of males after age fifty-seven due to

the fact that this older age group did not migrate in large

numbers to the cities.

Variations by Civil Divisions

As is generally known, there is considerable dis-

similarity in the age distribution of the major civil divi-

sions relative to the proportions of the young, those in the

productive ages, and the elderly [3:171-75]. In 1970 the

relative importance of those under fifteen years of age,

for example, ranged from highs of 50.6 percent of the popu-

lation in Zacatecas, 49.7 percent in Tabasco, and 48.8 per-

cent in Durango to lows of 42.5 percent in Yucatan and 41.5

percent in the Distrito Federal.

Equally pronounced were the variations in the propor-

tions of the population aged fifteen through sixty-four.

The proportions ranged from 55.1 percent in the Distrito

Federal, 52.9 percent in Yucatan, and 51.6 percent in Nuevo

Le6n to 47.0 percent in Tabasco and 45.3 percent in Zacatecas.

The least amount of variation is noted in the popu-

lations of those aged sixty-five and over. The relative

importance of this group ranged from 4.8 percent in Tlaxcala,

4.6 percent in Yucatan, and 4.4 percent in Puebla to 3.0

percent in Chiapas, 2.6 percent in the territory of Baja

California, and 2.5 percent in the territory of Quintana Roo.

The degree of the variation throughout Mexico in

-the relative importance of the children, those persons in

the productive ages, and the elderly can be noted easily by

the indexes presented in Table IV. If each major civil divi-

sion had contained in 1970 exactly the same proportion of

those persons in each age category that the age group con-

tained of the national population, all of the indexes would

be 100. For example, in Morelos 46.2 percent of the popula-

tion was under age fifteen, the same proportion as that in

the entire nation, so the index for Morelos is 100. However,

in the state of M4xico, 48.7 percent of the population was

less than fifteen years of age, whereas the corresponding

proportion for the nation as a whole was only 46.2 percent.

Thus, the state has an index number of 105.

As always, births; deaths, and migrations are the

three factors which are immediately responsible for varia-

tions in the relative importance of the different age cate-

gories. In 1970 the relatively high proportions of children

in the populations of Zacatecas and Durango, for example,

are due, in large part, to the heavy migrations of persons

in the economically productive ages out of the civil divi-

sions. Another factor is that these states have high pro-

portions of their total populations residing in rural areas

where the birth rate is known to be higher than in urban

districts. (See Table V.) The high rural birth rate is

also undoubtedly a major factor in explaining the high pro-

portion of the young in Tabasco. (Compare Tables IV and V.)

On the other hand, the low proportion of the young












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in the Federal District exists for the following two reasons:

(1) a very high proportion of the division's population is

urban and has a relatively low birth rate, and (2) there has

been a heavy flow of migrants into the Federal District,

thereby increasing the proportion of persons in the produc-

tive ages.

The very low proportions of the elderly in the state

of Baja California and the territory of Quintana Roo are ex-

plained primarily by the fact that these two civil divisions

have received relatively large numbers of migrants in recent

decades.* Consequently, they are inhabited largely by the

young and middle-aged rather than by the aged. On the other

extreme, the very high proportion of the elderly found in

Tlaxcala is due to a heavy migration of persons away from

the state for decades.

Dependency Ratios

The age profile of population also determines the

ratio which exists between the proportion of persons who

are in economically productive ages. Societies differ with

respect to the ages at which their members are expected to

be employed or gain a livelihood. In Mexico, for example,

it is not uncommon to find ten- or twelve-year-old boys

*In 1970 over 41 percent of the population of Baja
California had been born outside of the state, and in Quin-
tana Roo over 45 percent of the inhabitants were nonnative-
"born. Computed from [1:3, 57-66].

selling newspapers or shining shoes and girls of this age

working as domestic servants, at least part time. Neverthe-

less, for purposes of international comparison, this study

follows the total dependency ratio used by Smith, Hitt, and

others, which designates the dependent ages as those under

age fifteen and those aged sixty-five and over [19:56]. The

productive part of the population is therefore those persons

aged fifteen to sixty-four inclusive.

In 1970 the dependency ratio in Mexico as a whole

was 99.6 dependent consumers per 100 producers. (See Table

V.) This means that there were almost exactly as many per-

sons who were not in the productive ages as there were in

this category. Another way of stating this is to say that

one-half of Mexico's population is responsible for providing

goods and services for both themselves and the dependent

half. Such a task is enormous, particularly for a country

still very much in development. By way of contrast it can

be noted that the dependency ratio for the United States in

1970 was only 62.2. Thus, in Mexico as a whole, the load

of feeding and providing for its inhabitants was 60.1 per-

cent heavier than that of the United States, obviously a

nation much more developed and able to provide for its own


Within Mexico the ratio of dependents to producers

varies considerably between the urban and rural populations.

In 1970 the urban dependency ratio was 93.8, while for the

rural population it was 110.1. This difference becomes even

more significant when it is remembered that the approximate

median income of the economically active population which

was engaged in occupations such as those related to agricul-

ture, cattle-raising, and fishing was 59 percent lower than

it was for all other occupations combined.* This means that

the more urbanized civil divisions of the country such as

the Distrito Federal and Nuevo Le6n, which have propor-

tionately fewer dependents, but higher incomes, than the

more rural federal entities, must assume a major part of

the cost of services which the government provides for

those inhabitants who live in remote areas of the republic.

(See Table V.) In addition, high dependency ratios and low

incomes in rural areas are primary factors which have moti-

vated many young adults during the last few decades to mi-

grate from rural to already overcrowded urban areas through-

out Mexico. These migrations further augment the dependency

ratio in rural districts by reducing the proportion of pro-

ductive persons and necessitate an even greater burden on

the cities to divert the fruits of their labor force to help

support rural populations [4:59-60].

*Computed from [1:288].


From 1910 to 1921 there was a pronounced decrease in

the proportion of children under age fifteen and a slightly

less pronounced increase in the proportion of persons aged

fifteen to sixty-four, while the percentage of the elderly

rose slightly. (See Figure 5.) The decline in the propor-

tion of children in the population reflects the greatly re-

duced birth rate during the time of the Mexican revolution,

which lasted most of the eleven-year period. The corres-

ponding increase in the percentage of people aged fifteen to

sixty-four would have been greater had it not been for the

deaths of many adults during the war and during the great in-

fluenza epidemic.

From 1921 to 1970 there has been a tendency for the

proportion of children to rise continually with a concomi-

tant decrease in the percentage of persons in the productive

ages, while the proportion of persons aged sixty-five and

over continued to rise gradually. The major explanation for

these phenomena is the fact that while after the war the

birth rate rose rapidly, but quickly returned to a prewar

level and remained there over the five decades, the mortality

rate during the same period has been continually decreasing.

Since the infant mortality rate particularly has been re-

duced in recent decades, and the birth rate has not fallen,

the proportion of children has grown steadily greater.

- It should not be assumed, however, that the trend

I p I

1- ft
1564 YEARS
15-64 YEARS

**- "













1- -1--- -I- 1

1921 1930 1940

1950 1960 1970

Changes in the Proportions of People in
Three Broad Age Groups, by Sex, Mexico,

---- MALES



Figure 5.

of the last fifty years with respect to the increasing pro-

portion of children in the population will continue during

the decade of the 1970's. To the contrary, there are three

good reasons to believe that there will probably be a leveling

off of the percentage of persons under fifteen in the popula-


First, the death rate in Mexico has just about

ceased to drop, at least significantly, and it is now much

more difficult to reduce substantially the percentage of in-

fant deaths in the population.

In the second place, since migration toward urban

areas probably will continue in Mexico for the unforeseeable

future, and the birth rate for those living in the cities is

known to be lower than that for rural residents, in the near

future the nation's fertility rate should begin to decline


Third, the Mexican government has officially announced

a program to encourage family planning, effective as of

January 1973. Though it may take many years for such a pro-

gram to reduce the birth rate appreciably, certainly it will

make some contribution toward at least slowing the trend of

previous years.

The proportion of persons aged sixty-five and over in

Mexico will probably continue to rise gradually as the popu-

lation slowly ages. If there are unusual breakthroughs in

the methods of prolonging life, this rise could be more preci-




Among a person's most important characteristics is

whether he is male or female. A person's sex directly

affects his attitudes, activities, and needs, as well as the

social and economic roles within the society which he or she

plays [3:187-88].

Furthermore, the relative proportions of males and

females in a given population contribute greatly in determin-

ing the tempo and type of life which is carried on within

the society. Life differs greatly in mining camps, agricul-

tural districts, or pioneer areas, where males predominate,

from that in textile centers and residential cities, where

there are many more women than men [19:61].

As was mentioned in the preceding chapter, with re-

spect to the age factor, the sex composition of a popula-

tion is also very important, because the demographer must

control or correct for it if he hopes to isolate and measure

other significant variables. For example, it would be

pointless to compare the birth rate of the frontier terri-

tories of Baja California and Quintana Roo with that of the

highly urbanized Distrito Federal without making necessary

adjustments for the contrasting differences in the lack of

balance between the sexes of these major divisions of Mexico's

territory. In addition to affecting the birth rate, the

proportion of the sexes in a population also has a direct

bearing on the marriage and death rates.

Data and Indexes

In the present study the index used to analyze the

sex composition is the sex ratio, the number of males per

100 females, which is the index used most commonly by

demographers around the world. It is computed by dividing

the number of males in the given population by the number of

females and multiplying the result by 100.

One should keep in mind the following facts concern-

ing the manner in which births, deaths, and migrations

affect the sex ratio in a population: (1) at birth the

proportion of the sexes is relatively high, about 105 males

per 100 females, (2) usually at every age the mortality

rate for males is higher than that for females, (3) in mi-

grations of an international nature, in which long distances

are spanned, males far outnumber females, and (4) in migra-

tions where short distances are involved, such as the move-

ment from the countryside to cities nearby, females predomi-

nate among the migrants [3:195].

Since the question on sex is usually the simplest

_and most unambiguous inquiry on a census schedule, responses

to it are among the most reliable of any data gathered in

the enumeration of a population. However, imperfections in

the securing and tabulating of the data are manifested when

the sex composition of the population is broken down accord-

ing to residential and age groups. Each year an estimated

600,000 Mexican males, particularly from rural areas, mi-

grate to the United States, either legally or illegally,

and there is often a high degree of uncertainty with respect

to their return [74:1, 14]. Thus, there is a tendency to

miss some of these in the census enumeration. Unfortunately,

also, when the data on sex are broken down by age groups, it

becomes evident that the information is among the least

reliable in the census compilations. The reason for this is

that females in early adulthood tend to report themselves

as somewhat younger than their actual ages. Figure 6 and

Table VI have been prepared to illustrate this fact.

The sex ratio in Mexico at birth is around 105, and

at all ages the mortality rate among males is higher than

among females. As a result, in a total population unaffected

by large-scale wars or international migration, the sex ratio

should decline gradually with the increasing age until, in

the advanced ages, it becomes as low as seventy-five, or

even lower. Accordingly, the curve would reach the base

line 100 somewhere from about age thirty-five to forty-five.*

*For a more extensive discussion of how it can be
determined that women understate their ages, see [19:62-67;

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However, observing Figure 6 it is clear that the curve tends

to resemble a very elongated S lying on its side. While

the average sex ratio for the persons aged zero to nine is

well above 100, as expected, there is a precipitous decline

in the curve until it reaches a sex ratio of 91.8 in the

group aged twenty to twenty-four. Then, the curve reverses

itself and rises to 102.8 for the age group forty-five to

forty-nine, at which point another decrease begins and

carries the index down to 74.8 for the group aged eighty-

five and over.

Apparently, women who are twenty and older would

like to be considered a few years younger, and, consequently,

they purposely misstate their ages to the census enumerators.

This understatement of age causes women who, in reality, are

twenty to twenty-four years of age to be counted in the

fifteen-to-nineteen age group, some in the twenty-five-to-

twenty-nine group to be classed in the twenty-to-twenty-four

category, and so on. The result is that an abnormally high

proportion of women are enumerated as being aged fifteen

to twenty-nine, and a correspondingly low proportion of fe-

males are reported to be aged thirty to fifty-four, or there-

abouts. This causes a low sex ratio in the first group and

a comparatively high proportion of the sexes in the second.

In the advanced ages there is a tendency for women to over-

state their ages, thus reducing the sex ratio very sharply.

Table VI also indicates that the understatement of

women's ages is the factor which causes the S-shaped curve

of sex ratios by age. Excluding death and migration, the

persons who were in the age groups five to nine, ten to

fourteen, and fifteen to nineteen, in one census, would be

the persons aged fifteen to nineteen, twenty to twenty-four,

and twenty-five to twenty-nine, respectively, at the time

of a succeeding decennial census. If the ages were reported

correctly, the age groups for both males and females would

diminish by approximately the same percentage due to the

number of deaths. However, it should be noted that while

the proportionate reduction in the males is a total for the

three age groups of 30.9 percent over the ten-year period,

the corresponding decrease for the females is only 9.0 per-

cent. This discrepancy is due to the inflation of the num-

ber of females because of the practice of older women under-

stating their ages.

The discrepancies mentioned above destroy much of

the usefulness of the data on the composition of the popula-

tion when sex is cross-classified with age. Thus, the

reliability is particularly reduced in such indexes as the

rates of reproduction, expectation of life, marital status,

and educational status. In addition, the fact that women

report their ages as chronologically lower complicates

greatly the analysis of such matters as rural-urban migra-


Variations Within the Nation

In 1970 the Mexican census indicated that there

were 24,065,614 males and 24,159,624 females, or 99.6 males

for each 100 females. This comparatively high sex ratio is

due to a heavy concentration of the population in the

younger years of life. The ratio would be even higher if

Mexico were not losing each year a significant number of

males who migrate to the United States.

The sex composition varies considerably in Mexico,

as can be seen when one takes into account such factors as

age, place of residence, and ethnic composition of the

population. Actually, these factors always need to be taken

into consideration in order to interpret correctly the data

on sex. For example, if the total population of a civil

division had a sex ratio of only ninety-three and the popu-

lation was composed of a relatively high proportion of per-

sons living in urban districts, then this would have much

more significance in explaining a low marriage rate and

fertility rate than the mere fact that the sex ratio itself

was low.

Variations by Civil Divisions and Age

Table VII contains data showing the sex ratios in

the total population and in all of the major civil divisions

of Mexico in 1970, with the material for age further subdi-

vided so as to give the indexes for three broad age groups.



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It should be noted that the two territories, Quintana Roo

and Baja California, have the highest sex ratios in the

country. This is probably due primarily to the fact that

these are largely frontier areas which have attracted a

disproportionate number of males. In them the sex ratios

are especially high among persons in the economically pro-

ductive age groups.

In contrast to the high proportion of males found

in Mexico's frontier populations, in the Distrito Federal,

the nation's most populous and most highly urbanized civil

division, the sex ratio is only 93.4. Undoubtedly, such a

low index is due, in large measure, to the heavy influx of

females into the city to work as domestic servants and in

other occupations. The sex ratio of 89.7 among those per-

sons in the productive age group of the Distrito further

helps to substantiate this proposition. The extremely low

proportion of males among the elderly, 63.8, indicates,

not only that women outlive men, but that relatively few of

the females who migrated to the Distrito Federal have re-

turned to retire in the areas of Mexico from which they

came. Sex ratios for those aged seventy-five and over may

be somewhat lower than normal due to the deaths during the

years of the Mexican revolution of many males who now would

be in this age group.

Rural-Urban Differences

There are marked variations in the proportions of

the sexes of the rural and urban populations of Mexico.

Farming areas are generally characterized by very high sex

ratios, and urban populations, by very low ones. This holds

true for every major civil division in Mexico in 1970.

(See Table VIII.) The proportion of the sexes for the na-

tion as a whole was 104.6 in rural areas, while the sex

ratio for the total urban population was only 96.2. Also,

as might be expected, in the various major civil divisions,

the urban populations of places of less than 20,000 inhabi-

tants generally have higher sex ratios than those of the

larger, urban centers.

Among married persons, the proportions of the sexes

are approximately equal. Therefore, a high sex ratio in

rural areas means that a male engaged in agricultural pur-

suits who is seeking a wife has the odds against him,

whereas the low sex ratio in urban districts prevents

thousands of women in the cities from finding male life

companions. Both the marriage rate and the birth rate are

lower than what they would be if the proportion of the

sexes were balanced in rural and urban areas.

Table VIII also gives some indication as to which

major civil divisions have experienced a disproportionately

heavy internal migration of females from rural to urban

areas. This can be learned by comparing the sex ratios of


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the rural population with those of the urban areas having

20,000 and more inhabitants. Where a relatively large

difference exists between the sex ratios of those two seg-

ments of the population, as is the case in Campeche, Nayarit,

Sinaloa, and Tlaxcala, this type of short-distance migration

probably has occurred on a large scale. The prime example

of this phenomenon in Mexico is the heavy and constant move-

ment of young women to Mexico City from the rural areas or

civil divisions which are geographically near the Distrito


Variations among Nativity and Ethnic Groups

There are some notable differences between the sex

ratios of the various nativity and ethnic groups of Mexico's

population. The 1970 census reports contain data from which

one can compute the following proportions of the sexes

according to nativity: all native-born, 99.6, those born

in the civil division of residence, 100.8, those born in

another civil division, 92.6, and foreign-born, 103.7.

The sex ratio of the foreign-born is higher than

that of the total population (99.6), since those migrating

to Mexico from other countries have been predominantly males.

However, the number of males per 100 females among the

foreign-born has been considerably higher in previous decades.

For example, in 1930 it was 183.3, in 1940, 127.7, in 1950,

119.0, and in 1960, 116.2. Two factors which help to explain

this steady reduction in the sex ration are the higher inci-

dence of mortality among males and the fact that upon retire-

ment more women are accompanying their husbands from the

United States to take up residence in Mexico.

Since the absolute number of the foreign-born in

Mexico was quite small, only 191,184 persons in 1970, the

proportion of the sexes among all the native-born is the

same as that of the total population.

The notably lower sex ratio among the native-born

who have migrated to a civil division other than the one of

their birth would seem to indicate that a proportionately

higher number of females have migrated within the country

than have males. Also, as has been stated above, a sizable

number of the women who have migrated to the cities are not

able to find husbands and thus live out the remainder of

their lives unmarried.

The differences in the proportion of males and fe-

males among the various ethnic groups deserves special

comment. While the census of 1970 does not classify the

nation's inhabitants according to race, a classification by

sex is made as to whether or not a person aged five or

above speaks one of Mexico's indigenous languages. It is

apparent that the sex ratios among all persons in this

ethnic segment of the population will be slightly lower

than if people of all ages were included. For example, the

proportion of the sexes of the total population aged five

and above is only 98.9, as compared to 99.6 among the popu-

lation of all ages.

Since the percentage of Mexico's population which

speaks an indigenous language is comparatively small, less

than 8 percent, it is not surprising to find that the sex

ratio among the nonindigenous-language-speaking segment of

the population is 98.6, very close to that of the total

population aged five and above. The sex ratio among those

persons who speak Spanish as well as an indigenous language

is 117.2. This high ratio demonstrates that the rural-urban

migrations of females are particularly heavy among those

who have learned Spanish. Many girls and young women of

indigenous background who can speak the nation's principal

language are in demand as maids in Mexico City and other

large, urban centers of the country.


Ordinarily, changes in the proportions of the sexes

in a country result, to a great extent, from the amount of

immigration and emigration which has transpired. In the

case of Mexico, throughout the twentieth century immigration

has been almost negligible in proportion to the total popu-

lation. The percentage of foreign-born reached its peak

in 1921, 1.4 percent of the total population. It is very

difficult to know the exact extent of emigration across

-the years, but it is certain that considerable migration to

the United States has taken place in recent decades, par-

ticularly on the part of the Mexican males. Perhaps this

migration has been extensive enough to lower the sex ratio

by approximately one whole point. For example, in 1970

if an estimated 300,000 Mexican males who remained in the

United States illegally were added to the total Mexican

male population of that year, the sex ratio would have been

100.9 rather than 99.6.

Changes in the mortality rate have contributed more

than any other factor to the marked variations in the pro-

portions of the sexes from decade to decade. (See Figure 7.)

Before the Mexican revolution, both high death rates and

high birth rates kept the'sex ratio at 98.5 in 1900 and 98.0

in 1910. Then, due to the carnage which occurred during

the revolution, the number of males per 100 females plunged

to an all-time low of 95.5 in 1921. After the revolution

the sex ratio increased relatively rapidly to 96.3 in 1930,

97.4 in 1940, and 97.0 in 1950. The slight decrease between

1940 and 1950 may have been due to a greater influx of

Mexican males into the United States during the years of

World War II when they helped to fill job vacancies left

by American men who entered the military services.

Marked improvements in the field of medicine during

and after the Second World War permitted Mexico to lower

its death rate, particularly among infants, thereby per-

mitting more males to enter the population. Also, after

I -- I ---- I ---- 1 ---- I ----



96 1-




I -



" D.F.

1900 1910 1920 1930 1940 1950 1960 1970

Figure 7. Changes in the Sex Ratios in Mexico and the
Distrito Federal, 1900-1970