The rate of increase in the number of persons in both the youngest and oldest age groups of the population between 1950 and 1960 was five times that of the groups in the intermediate ages. The increased number of births during and after World War II was responsible for the growth of the younger groups.

Factors influencing the increase in the number of elderly persons were the upward trend in the number of births in the late 19th century, declining mortality, and immigration during the early decades of the 20th century. The number of persons under 18 years old increased by 37 percent and the number 65 and over increased by 35 percent, whereas the increase in the age group 18 to 64 years was only 7 percent.

Largely because of the persistence of fairly high levels of fertility throughout the decade, the median age of the population fell slightly, from 30.2 years in 1950 to 29.5 years in 1960. This is the first time in the recorded history of the United States that the median age has declined during an intercensal period, counter to the trend which had been in evidence for more than a century.

The large table shown here is a preprint of table 59 from Final Report PC(1)-1B, which contains additional summary information on the general characteristics of the population.

The PDF to the right contains the 8-page report.