demographic yearbook annuaire demographique 1951

population bases for different dates within the year (e.g., the
midyear population in the crude rate table and the population
at the census date in the age-specific rate table) are
not noted. These differences are very small, seldom amounting
to more than one unit in the decimal place.
Table 72 presents a summary of crude death rates for
64 areas, during the period 1905 to 1930. This is a companion
table to the one presenting crude birth rates for the
same period (table 5). These rates are averages for the
periods 1905-1909, 1911-1913, 1921-1925 and 1926-1930
and were taken from the League of Nations Yearbook.
1 able 73 gives the total number of deaths for each year,
1935 to 1950, as reported for 143 areas. The geographic
coverage represented by these data is somewh_at less than
that implied by the number of areas. In a number of cases
the statistics are confined to the non-indigenous segments
of the population. As a consequence, the data for some
regions, and particularly for the continent of Africa, are of
only minor significance.
Table 74 presents annual crude death rates for the period
1930 to 1950 for 131 areas. Despite the many limitations
already described, which affect the accuracy, comparability
and geographic coverage of these data (not to mention the
limitations that always apply with respect to crude rates),
they nevertheless present the most comprehensive survey
of general levels and trends that is so far available.
The crude rate is the number of deaths reported for a
calendar year per 1,000 persons present in the same geographic
area at the mid-point of the year. Wherever possible,
rates which do not represent complete coverage either
of geographic areas or of segments of population, or in which
there is some lack of correspondence between the two components,
are so noted. Rates are not shown where the coverage
of the death statistics differs importantly from that of
the available population base.
Table 75 presents statistics of deaths for recent years, classified
by month of death. Data are shown for 83 areas and
cover periods ranging from 1 to 4 years. In so far as possible,
the distribution is by month of occurrence rather than by
month of registration, but in a number ofcases monthly data
were available only on a date-of-registration basis. Figures
indicated as provisional generally refer to the month of
registration and are likely to differ slightly from annual
totals shown in other tables. The usefulness of the data for
the purpose of seasonal analysis is therefore somewhat restricted.
However, most of the countries for which statistics
are shown have efficient registration systems and the monthto-month
fluctuations in the number of deaths registered
may be expected to reflect rather closely the month-tomonth
fluctuations in the number of deaths that occurred.
Table 76 and table 77 present statistics of deaths classified
by age and sex for the period 1936 to 1950. The annual
numbers are given in table 16 for 91 areas. Figures are shown
for each sex, but, for reasons of space, not for the two sexes
combined. Deaths of unstated sex are therefore excluded
and the implied totals occasionally differ from those shown
in table 13. The numbers so excluded are given in footnotes
except where the exclusion was regarded as without significance
and, even then, the exclusion is noted unless the
number involved was less than 10.
The age classification is in the main based on the dates
of birth and death and is expressed in completed years.
Some countries, however, base the age classification on the
year of birth, the age at death being determined by subtracting
the year of birth from the year of death. The only
country known to follow this procedure is Norway. For that
country statistics of infant deaths are shown by year of birth
in table 16, but are adjusted to date of birth in the infant
mortality tables.
Death rates specific for age and sex are presented in table
17 for 54 areas. The accuracy of these data is subject to the
same kinds of reservations regarding deficiencies in statistics
by age as those discussed heretofore. The number of countries
and years for which data are shown is considerably
smaller than in the preceding table, statistics of the population
by age being less frequently available than statistics
of deaths by age.
In computing the rates, deaths at unknown ages and the
population of unknown age were disregarded except as they
formed part of the death rates for all ages combined. Each
rate is, therefore, the number of deaths at a given age that
occurred during the course of a year per 1,000 persons of
that age at the middle of the year or at another date within
the year. It should be noted that the rates for persons under
1 year of age in this table differ from the infant mortality
rates shown in table 19, the latter being based on live births
for the year rather than on the population under 1 at the
middle ofthe year. Also, the rates for all ages combined differ
in a number of cases from those shown in table 14, the reason
being that they are based on the total population at the
same date as that for which an age distribution was available
for the computation of age-specific rates (usually a
census date). In a few instances the difference is attributable
to the fact that the rates in this table were based on the
mean population (obtained by averaging age data for two
successive Decembers), whereas the corresponding rate in
table 14 is based on an estimate for 1 July. Differences of
these types are very small and are not noted in the table.
The problem of obtaining precise correspondence between
the deaths of the population in the inclusion or
exclusion of armed forces, refugees, displaced persons and
other special groups is particularly difficult where agespecific
rates are concerned. In cases where it was not
possible to achieve such a correspondence, the differences
in coverage are noted. Male rates in the age range 20 to 40
years, particularly during the war period, are affected by
this non-correspondence and care should be exercised in
using these rates for comparative purposes. It should be
added that even when deaths and population do correspond
the comparability of the rates may be affected by abnormal
conditions such as absence from the area of large numbers
of young men in the military forces. The result is that death
rates appear high in these ages, simply because a large section
of the able-bodied members of the age group, whose
death rates under normal conditions would be less than the
average for persons of their age, have been removed from
the computations.
Because of the general confusion surrounding this problem,
the disposition of armed forces, as regards both the
population base and the deaths, is noted in all cases where
the disposition could be ascertained and where there might
be some question as to the exact coverage of the two components
of the rates.
Tables 78 to 27 present statistics of infant mortality (deaths
of infants less than 1 year of age). The completeness and
accuracy of these statistics are highly variable. There is some
evidence that the underregistration of deaths is proportionately
greater for infants than for other ages.
Table 78 gives the total number of infant deaths for 120
areas for the period 1935 to 1950, and table 79 gives infant
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