the aged will also decline. It is predicted that the proportion of the population of the aged will be slightly lower than the 2050's 32% Ievel, and then it will reach 28.8% in 2100.
Examining the differences on the aging trend in reference to the assumption on the future fertility rate, there are discrepancies of 1.7 points between 28.2% of the low variant and 26.
5% of the high variant in 2050 (refer to Figure 6). The differences indicate that the future fertility rate level will have an impact on the aging, and the gap with the aging level will be further widened over the years. At year 2050 there will be a gap of 6 points between the 29.2% high variant and the 35.2% low variant. Thus, if the society with a low fertility rate continues for a long period of time, it indicates relatively that the aged society will continue to increase.
Changes of Population Pyramid
The population pyramid of Japan shows that Japan's overall population will become aged because of the rapid increase and decrease of the past fertility rates (e.g. 1st baby boom - rapid growth of fertility rate between 1947 and 1949 and echo effect - rapid decline of fertility rate between 1950 and 1957). Furthermore, high and low birth rate repeatedly fluctuated thereafter. Thus, the pyramid shows frequent up and down or rough contours (refer to Figure 7-1, 7-2, 7-3, and 7-4) .
From the 1995's population pyramid, the 1st baby boom generation appears at the second half of the 40 years of age and the 2nd baby boom generation, those who are born between 1971 and 1974, appears at the 1st half of the 20 years of age. In 2025 the 1st generation will reach the 1st half of age 70, and the 2nd generation will reach the 1st half of age 50. The aging
population up to the year 2050 is centered around the 1st generation baby boomers. On the other hand, the elevated aging level around 2050 was caused when the 2nd generation baby boomers became aged. Also it was affected by the continuously low fertility rate. It reflects that the size of the population will shrink on every generation. Thus, the population pyramid of Japan will transform from the pre-war shape of Mr. Fuji to the shape of a temple bell in 1995 to eventually the shape of a vase in 2050.
Changes of Population Dependency Ratio
There is a population dependency ratio, which is an index number to indicate the degree of the burden of support by the working age population, which can compare relative differences between the children's and the aged population. The old aged dependency ratio based on the medium variant (value = aged population - working - age population) will rise
from the current level of 21% (4.8 workers to support 1 old aged dependent) to 45% level (2.2 workers to support 1 old aged dependant) in 2020 (see Figure 8). By 2050 it is projected that the child dependency ratio (value = children's population - working-age population) will shift from the present level of 23.0% (1 child dependant supported by 4.3 workers), and thereafter will range from 21 to 24% level.
