No. 1 Japan

2010 Population: 127,370,000
Forecast 2050 Population: 95,152,000
Percent Decrease: 25.3 percent
2010 Population over age 65: 23 percent
Fertility Rate: 1.4
Net Migration Rate: -1

Japan has been aging rapidly over the last 20 years. The number of people over age 65 doubled from 7.1 percent of the total population in 1970, to 14.1 percent in 1994, according to Japan's statistics bureau. Today the country has the world's largest concentration of elderly at 23 percent of the total population. This, combined with a low fertility rate and an excess of emigrants, make Japan the world's fastest-shrinking country. By 2050, its population is expected to have declined by one-fourth from its current level.