demographic yearbook annuaire demographique 1951

Foreword
The third issue of the Demographic Yearbook presents data culminating so far as possible with the
year 1950.
The geographic coverage of the basic tables on total population, births, deaths and marriages has been
extended. The initial year for which annual crude rates are shown has been moved back from 1932 to 1930
and retrospective tables giving average crude birth and death rates for selected periods between 1905 and 1930
have been added.
Because of the space required for the presentation of statistics of the population classified by age and sex,
only new data or data not yet published in the Yearbook are presented this year. Occasion has been taken to
include data for certain small areas that may be of special interest from the ethnic and demographic points
of view.
The tables dealing with economic characteristics of the population have been omitted because very little
new information is available.
The present issue of the Demographic Yearbook is devoted mainly to the subject of mortality. The
statistical tables contain comprehensive data on deaths classified by age and sex, by cause of death and by
month of occurrence. Statistics of infant deaths, both totals and classifications by subdivisions of the first year
of life for each sex, are also given. The corresponding rates are shown wherever feasible. Statistics of stillbirths
have been added to the section dealing with vital statistics. Tables presenting selected life table functions
included in the first volume but not in the second, are shown again this year, considerably extended and
brought up to date.
A chapter on recent mortality trends and a chapter on the development of statistics of causes of death
are also included. Neither of the purports to be an exhaustive analysis, but each furnishes some foundation
for the interpretation of the data presented in the tables.
As the subject of emphasis shifts with successive issues of the Yearbook, the nature and detail of the
statistical tables change considerably. A cumulative index of table titles covering the first three issues of the
Yearbook has therefore been included for the convenience of the users of these data.
In addition to the changes already mentioned, this issue presents, for the first time, statistics of divorces.
Annual totals for the years 1935 to 1950 are shown.
The bibliography presented at the end of the volume is a supplement to the one presented in the
second issue. In order to conserve space, only new items are listed. Continuing publications such as yearbooks
and periodicals are listed only if they did not appear in the previous list.
Total population counts, some preliminary and some final, are shown for most of the censuses conducted
in 1950 and 1951. Current data on total population are accordingly of a somewhat higher order of reliability
than heretofore.
The appraisal of the quality of the data presented in the Yearbook has been carried forward. The
classification of population estimates, first presented last year, has been revised and elaborated, and appears
again in the form of a code in table 1. A somewhat simpler code has been developed for the classification of
vital statistics with respect to their general reliability and has been incorporated in the tables presenting
total births, deaths, infant deaths, marriages and divorces and in the tables presenting the corresponding
crude rates. It is now possible to determine at a glance which of the series are officially held to be complete or
virtually complete in coverage, which are admittedly incomplete or subject to significant irregularities in
registration and which are of undetermined reliability and therefore to be interpreted with caution. This
classification is too broad and too subjective to be of great value for purposes of refined analysis. It is planned
to develop more objective and more sensitive criteria for the classification of vital data.
With the progress in tabulation of the 1950 and 1951 census results, it is believed that sufficient data
will become available during the coming months to permit publication of statistics on the geographic
distribution of the population in the fourth issue of the Demographic Yearbook. If so, that will be the topic
of major emphasis next year.
Most of the statistics presented in the Demographic Yearbook are derived from questionnaires sent by
the Statistical Office of the United Nations to the governments or administrations of all the geographic units
or "countries" of the world. These data are supplemented where feasible from national official publications.
The statistics of international migration are furnished by the International Labour Office. The bibliography
was prepared by the Census Library Project of the United States Bureau of the Census and the Library of
Congress.
Special acknowledgement is made to the Population Division of the United Nations Department of
Social Affairs for assistance in the preparation of Chapter I, in the appraisal of the quality of the demographic
statistics and in the planning of the content and form of this issue of the Yearbook.
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