A comparison of the Japanese population by age group between the beginning and the end of the high-growth era clearly points to a rapid increase in the Japanese working-age population taking place during the period as confirmed by Chart 4 showing a blip moving upward in the population pyramid.
For your reference, the average growth rate of the total population and the growth rate of the working-age population from 1955 to 1975 were 1.3 percent and 1.9 percent, respectively. A quick cross-country comparison can confirm that Japan’s population and the growth rate of the working-age population in those days were relatively high, or sometimes even the highest, among the advanced countries.