age 25 is measured on the vertical axis, the percentage aged 60 and older on the horizontal axis, and the percentage aged 25–59 can be represented by diagonal gridlines. Only the 50 percent gridline is shown. In 1950, no Asian country had a large population concentration in the prime working ages. India’s population was somewhat younger than that of the People’s Republic of China (PRC), and Japan’s age structure was very similar to
the PRC’s.