Older adults wait in line to receive free food in Seoul on Christmas Eve, Tuesday. Korea has become a "super-aged" society, a concept defined by the United Nations, when citizens aged 65 or older account for 20 percent of its population. Newsis

Korea has become a "super-aged" society, a concept defined by the United Nations, as the proportion of citizens aged 65 or older accounts for 20 percent of its population, according to the Ministry of the Interior and Safety on Tuesday.

The number of Koreans in that age group reached 10,244,550 on Monday, accounting for 20 percent of the nation's total population of 51,221,286.

The United Nations classifies countries where more than 7 percent of the population is 65 or over as an aging society, those with more than 14 percent as an aged society and those with more than 20 percent as a super-aged one.

Since the late 1980s, the proportion of the older adult group has rapidly increased amid the country's declining birthrate. In 1990, the figure stood at 5.1 percent; then, it took only 20 years to reach 11 percent before hitting 20 percent 15 years later. If the trend continues, it is projected to reach 25.3 percent in 2030 and 40.1 percent in 2050, according to Statistics Korea.

Graphic by Cho Sang-won

According to ministry data, the number of older women stood at 5.69 million, compared with 4.54 million men.

The age group accounted for 27.18 percent of the population in South Jeolla Province — the highest among the country's major regions.

Sejong, the country's administrative capital, had the lowest share at 11.57 percent. In Seoul, older adults accounted for 19.41 percent of the population.

"There should be a fundamental, systematic change to our (population) policy, including the establishment of a government department dedicated to this work, as we usher in a new era in which the proportion of the population aged 65 or over is higher than 20 percent," Kim Min-jae, a senior ministry official, said in a statement.

Creating a new ministry for all issues related to population management was one of the key election pledges of President Yoon Suk Yeol. But it never came to fruition amid the political stalemate at the National Assembly. After lawmakers impeached him over his short-lived imposition of martial law on Dec. 3, it could take months, if not years, before materializing through legislation.

To address rising pension costs and the shrinking working-age population, Lee Joong-ken, chairman of the Korean Senior Citizens Association, proposed raising the minimum age for eligibility for older adult welfare benefits from 65 to 75.

This suggestion comes amid years of political debate over whether the country should raise the age that defines older adults. That age serves as the criterion for determining retirement ages at companies and for the government's provision of various welfare programs as the older adult population continues to grow.

With its total fertility rate below 1, the world's lowest level, Korea is expected to feel the social and economic impact of the drastic demographic change in the coming decades.