Japan's population is expected to fall to 87 million by 2070, shrinking 30 percent from 2020, a government estimate showed Wednesday, highlighting the country's need to overhaul its social security systems and restructure its urban communities.

Foreign residents, including students and workers residing in Japan for more than three months, are set to comprise 10.8 percent of the population at 9.39 million in 2070, expanding from 2.2 percent in 2020.

The National Institute of Population and Security Research said those aged 65 or above in Japan are projected to hit 33.67 million in 2070 after peaking at 39.53 million in 2043. In 2070, they will comprise 38.7 percent of the population, resulting in ballooning social security costs.

The health ministry's research body provides 50-year demographic forecasts approximately every five years based on public data such as censuses. The government will use the latest data to calculate the country's future pension payouts.

The population, numbering 126.15 million as of 2020, is expected to fall under the 100 million threshold in 2056, it said.

The projected fertility rate, or the expected number of children born per woman during her child-bearing years, was at 1.36 for 2070, slightly up from 1.33 in 2020 but remaining well below the threshold of 2.07 for maintaining the population.

The number of births, which slipped below 800,000 in 2022, is likely to decline further to under 700,000 in 2043 and below 500,000 in 2070, the institute said.

People aged 15 to 64, the working-age population that supports the country's social security systems by paying premiums, are forecast to decline sharply to 45.35 million in 2070 from 75.09 million in 2020.

Those aged 14 and under are estimated to decrease to 7.97 million in 2070 from 15.03 million in 2020.

The population's average age is projected to be 47.6 in 2020, rising to 54.0 in 2070.

Men's average life expectancy is expected to reach 85.89 in 2070 from 81.58 in 2020, while that of women is likely to climb to 91.94 from 87.72.

However, according to Masashi Kawai, director of a research center on population decline prevention, the latest data "overstates the rise in the foreign population and does not take into account pandemic-caused falls in the younger generation's desire to marry or have children."

Stressing the need for a "strategic shrinking" of society as commercial and government services become untenable, he called for establishing compact cities of around 100,000 people offering centralized services.

Japan has slid down the global population rankings, going from the seventh most populous nation in 1990 to 11th by 2022. It is projected to drop to 17th by 2050, falling behind countries such as Vietnam and the Philippines.

South Korea is also grappling with a plummeting birth rate. Its 2022 population of around 51.8 million is expected to shrink to 45.8 million by 2050.

United Nations data from the end of July 2022 showed China was the world's most populous nation, followed by India and the United States. But India is expected to surpass its neighbor by the end of April and to remain at the top into 2050.

Related coverage:

Japan mulls expanding scope of skilled worker visa with no stay limit

Japan's population falls under 125 mil., 12th year of decline

FOCUS: Calls grow for drastic steps to address Japan's sliding birthrate