The population decline of Japan’s younger generation is progressing very quickly, even from a global perspective. In Japan, the percentage of young people in the population grew since the 1950’s until it peaked in 1970 at 35% of the population. Since then, the percentage of young people in the population rapidly decreased until 1990. From 1990 to 2005 the percentages levelled at around 27%, but then started to decrease again. It is estimated that by year 2035 the percentage of young people in the general population will drop below 20%, and steadily decrease over the long-term until year 2090. The population ratio of young people in other countries differs from Japan, in that the steady decline in the young population hit bottom in the latter half of the 1960’s, then in the 1970’s, while Japan’s youth population went into decline, the other countries’

Graphic 10 Youth Population Ratio Trend by Country

Source) Developed by MLIT based on : Medium-variant assumptions from United Nations “World Population Prospects: The 2010 Revision” for other countries; for Japan before year 2010, from MIC “Population Census of Japan”, for Japan from year 2015 and beyond, from IPSS “Population Projection for Japan (2012 January estimate)”

young population began to grow, until right around the 1990's when it began to fall. Therefore, though the youth population in other countries are also estimated to continue to decline in the long-term, the estimates also show that in other countries the percentage of younger people in the population will converge in the first half of 20%, which shows that the speed and amount of decline is less acute, compared to the decline of the youth population in Japan (Graphic 10).

## (Increase in One-Person/Couple-Only Households and Shrinking Households)

Along with population decline, falling number of birthed infants, and aging population, the household composition has also been changing. While Japan’s total population started to decrease, the total number of private households has been steadily increasing, from 22.16 million households in 1960 to 51.84 million households in 2010. According to estimates calculated by IPSS, the total number of private households will continue to rise until it reaches its peak in year 2019 (53.07 households), and then begin to fall to where households will have declined to approximately 49.56 million by year 2035.

The rise in the number of households is largely due to the increase in one-person households, couple-only households, and one-parent-and-child(ren) households. One-person households have been consistently increasing since 1960, when it stood at 3.58 million households (16.4%). However, due to a rise in the number of senior citizens living alone, and a growing trend in people remaining unmarried or delaying marriage until later in life, the number of one-person households has been increasing at a faster rate since the 1990's. In 2010, the number of one-person households reached 16.78 million (32.4%), and though the total number of private households are expected to start falling by year 2020, the number of one-person households are expected to continue to rise, with an estimated 18.72 million (36.5%) one-person households by 2030. As for couple-only households, the number has continually increased, from 1.63 million (7.4%) households in 1960, to 10.27 million (19.8%) households in 2010. This number has been estimated to increase until year 2020, when it is expected to start falling. The percentage of a married couple only households within the total number of private households, however, is expected to continue to rise, from 19.8% in 2010, to 20.8% by 2020, and 21.2% by 2035.

Meanwhile, the number of households of couple-and-child(ren)—which at one time accounted for over 40% of the total number of private households—started declining after reaching its peak in 1985 with 15.19 million households. Hereafter this number is expected to decrease faster; with estimates calculating that from 14.47 million (27.9%) households in 2010, the number will fall to 11.53 million (23.3%) households by 2035.

In the current state of population decline, the changes in household composition and continued increase in the number of households indicate that households are shrinking, and that the average number of people in a household will continue to decrease over the long-term. The average number of people in a household in 1960 was 4.14 people, but in 2010 the average was 2.42 people, and by 2035 the average is expected to fall to 2.20 people per household (Graphic 11).