Japan's seniors accounted for 29.1 percent of its population as of this month and 13.6 percent of its labor force in 2020, both record highs, government data showed Sunday, giving further evidence of a rapidly graying society.

The number of people aged 65 or older in the country, which has the world's oldest population, totaled a record-high 36.4 million, up 220,000 from a year earlier, according to the data by the Ministry of Internal Affairs and Communications prior to Monday's Respect for the Aged Day holiday.

The ratio of seniors remained well above 23.6 percent in Italy, the second most aged society, followed by 23.1 percent in Portugal, the ministry said, also citing U.N. data.

According to the ministry, the number of Japanese men aged 65 and older stood at 15.83 million, while that of women came to 20.57 million.

By age group, the number of people aged 80 or older totaled 12.06 million, up 460,000 from a year earlier, and that of those aged 90 or older reached 25.9 million, including 80,000 centenarians.

The National Institute of Population and Social Security Research projects that Japan's elderly will make up 30.0 percent of the population in 2025 and 35.3 percent in 2040.

The number of seniors with jobs increased for the 17th consecutive year since 2004. Of the 9.06 million elderly with jobs, 3.67 million were women.

The biggest employer of seniors was the wholesale and retail industry, with 1.28 million elderly workers, followed by agriculture and forestry with 1.06 million.

The ratio of those aged 65 or older with jobs reached 25.1 percent, the second-highest among major economies.

According to Organization for Economic Cooperation and Development data, the ratio in South Korea was the highest among the major economies at 34.1, while that of the United States and Canada was 18.0 percent and 12.8 percent, respectively.