For the first time, Japan's over 75s account for over 15 percent of the population after their cohort rose by 720,000 to 19.37 million people, government data released Sunday showed, in further evidence of the country's rapidly graying society.

Also hitting record highs this year were the over 65s, or seniors, accounting for 29.1 percent of the population, or 36.27 million people, according to Ministry of Internal Affairs and Communications data released ahead of Monday's Respect for the Aged Day holiday.

Japan tops the world rankings for oldest society by proportion of over 65s, well above Italy in second place at 24.1 percent and third place Finland with 23.3 percent.

The National Institute of Population and Social Security Research projects seniors to make up 35.3 percent of the population by 2040. A surge in elderly people presents problems for the country, including in health care system improvements and efforts to reverse low birth rates and sustain regional communities.

Government data from 2021 also showed that the number of employed seniors had risen for an 18th consecutive year, increasing by 60,000 to 9.09 million.

While the proportion of over 65s working was on par with last year's 25.1 percent, for the first time, the majority of people aged 65 to 69 -- 50.3 percent -- had a job. Seniors comprised 13.5 percent of the workforce, 0.1 point below last year's record high.

But there were signs of seniors quitting their jobs due to the effects of the coronavirus pandemic, with a notable trend of decline seen since August 2021.

According to the data, as of Thursday, some 15.74 million male seniors and 20.53 million females are aged 65 or over. The rise in the over 75s is attributed to the children of the first baby boom of 1947 to 1949 reaching their 75th birthdays.

About 12.35 million people are aged 80 and older, or 9.9 percent of the population, and around 2.65 million people are in their 90s -- roughly 2.1 percent of the country.

When the communications ministry released the same figures last September, it reported that there were around 36.40 million seniors in the country, but the data was later revised down based on the 2020 national census to 36.21 million.