TOKYO -- Single-member households will account for roughly 40% of households in Japan in 2040, according to estimates by the National Institute of Population and Social Security Research released on April 19.
The proportion of single-member households is expected to surpass 30% in all of Japan's 47 prefectures and reach 48.1% in Tokyo, with the national average coming to 39.3%
The increase in such households is attributable a declining birthrate and aging of the population, as well as the concentration in urban areas of younger people choosing not to marry.
The research institute releases its estimates on households across the country's 47 prefectures every five years. Based on the 2015 census, the institute estimated the trends of households in Japan until 2040 -- by which time all children of baby-boomers, who were born between 1971 and 1974, will have turned 65.
According to the estimate, the total number of households in Japan will decrease from 53.33 million in 2015 to 50.76 million in 2040.
However, the proportion of single-member households is set to grow, with the number expected to increase from 18.42 million households to 19.94 million over the same period. In particular, the growth of single-member households is expected to be high in Saitama, Chiba and Kanagawa prefectures around Tokyo, ranging from 12 to 20%.
The number of single-member households comprising elderly people aged at least 65, which stood at 6.25 million in 2015, accounting for 11.7% of all households, will likely rise to 8.96 million by 2040, or 17.7% of the total.
By prefecture, the ratio of solitary households comprising elderly people is estimated to surpass 20% in eight prefectures including Japan's northernmost prefecture of Hokkaido and the western Japan prefectures of Osaka, Ehime and Kochi in 2040. The number of single-member households consisting of those aged 75 or over will come to 5.12 million in 2040, or 10.1% of the total. The ratio will likely surpass 10% in 29 prefectures. Among them, the figures for the southwestern Japan prefectures of Kagoshima and Miyazaki, Kochi Prefecture, and the northern Japan prefecture of Akita are particularly high, at 14.8%, 13.2%, 13.9% and 13.3%, respectively.
The proportion of households headed by those aged at least 65 among the total number is expected to grow to 44.2% in 2040, up from 36% in 2015. The figure will top 40% in 45 prefectures, excluding Tokyo and Aichi, where the populations are younger, in 2040. The corresponding ratio will rise to over 50% in 10 prefectures, consisting mainly of those in the Tohoku region in northern Japan. The figure for Akita Prefecture in Tohoku will be particularly high, at 57.1%.
(Japanese original by Ryosuke Abe, Lifestyle and Medical News Department)