Mortality change and slowed population growth in developing countries.
A modest decline in the growth rates of developing countries has occurred in recent years. The principal reason for this has been a decline in fertility. Recently, reported changes in mortality trends have been noted, particularly mortality declines in many parts of the 3rd world. As indicated in a United Nations table of projected and reported crude birth, crude death, and population growth rates in the less developed countries (1960-1965 and 1970-1975), the United Nations foresaw a decline from 42.0/1000 to 39.0/1000--a decline of 3.0 points--between the 1960-1965 and 1970-1975 crude birth rates. However, by 1978 the reported 1960-1965 birth rate was actually 40/100 rather than 42.0/1000 and the 1960-1965 to 1970-1975 decline was 4.5 rather than 3.0 points. The United Nations projected the crude death rate to be around 18.8/1000 for 1960-1965. The expectation was that it would decline by 4.5 points to 14.3/1000 for 1970-1975. Instead, by 1978 the death rate decline had been only 3.6 points, from 16.8/1000 as then observed for 1960-1965 to 13.2/1000 in 1970-1975. This was 0.9 points less of a decrease than projected in 1968. As a result of these 2 influences working together, the 3rd world's population growth rate fell by 0.9 points between 1960-1965 and 1970-1975 instead of rising by the 1.5 points earlier foreseen. 37.5% of the divergence between the projected and realized population growth rates was attributable to the fact that the crude death rate declined less rapidly than anticipated. It is of considerable interest that the figures from the most widely used set of population estimates point to mortality in addition to fertility as a significant cause of the unexpected slow rate of population growth between the early 1960s and the early 1970s. Had it not been for the shower than expected mortality decline, there would have been no reduction in developing country population growth between 1960-1965 and 1970-1975.