Over a fifth of Japan's population is now 70 years old or older, the government revealed in a data release Sunday.

The data, released by the Internal Affairs and Communications Ministry ahead of Respect-for-the-Aged Day on Monday, showed that the 26.18 million people 70 or older accounted for 20.7 percent of the population as of Saturday — up from 19.9 percent last year and crossing the 20 percent line for the first time.

With retirees ballooning and the population shrinking under a low birth rate, the government needs to address its snowballing social security costs and a labor shortage that is hampering the nation's productivity.

In total, the ranks of the elderly — defined as those 65 or older — have grown to a record 35.57 million, up 440,000 from the previous year and accounting for 28.1 percent of the total population, also a record.

In another first, elderly women crossed the 20 million line at 20.12 million, substantially outnumbering the nation's 15.45 million elderly men.

Japan's 28.1 percent population ratio for seniors is the highest in the world, followed by Italy at 23.3 percent, Portugal at 21.9 percent, and Germany at 21.7 percent, the ministry said.

The National Institute of Population and Social Security Research estimates that Japan's ratio will reach 35.3 percent in 2040.

Japanese also appear to be living longer, with those 80 or older at 11.04 million, up 310,000 from the year before, and those 90 or older at 2.19 million, up by 140,000.

On the employment front, seniors who still have jobs rose for the 14th consecutive year to a record 8.07 million in 2017, accounting for 12.4 percent of those employed. Among them, 3.16 million, or three out of four, were part-time or other types of nonregular employees.