The number of people aged 20 years old, the legal age of adulthood in Japan, is set to reach an record-equal low of 1.21 million on New Year's Day, government statistics showed Thursday.

The new adults, down 50,000 from a year earlier, make up 0.95 percent of Japan's total population of around 126.83 million — falling below 1 percent for the sixth straight year since comparable statistics were first compiled in 1968, according to the Internal Affairs and Communications Ministry.

Of the 1.21 million, which is on par with a record low logged on Jan. 1, 2014, 620,000 are men and 590,000 are women.

The year-on-year decline in the total number of new adults follows the first increase in 21 years in 2015 with many baby boomers becoming parents roughly two decades ago.

The number of people aged 20 years old is expected to fall to 1.06 million in 2025, according to estimates by the National Institute of Population and Social Security Research.

With 2016 the Year of the Monkey, according to the 12-sign Chinese zodiac, the number of people born in previous such years in Japan stands at 9.91 million, with about 4.80 million men and 5.12 million women, the statistics showed.

Around 2.4 million people aged 18 and 19 will join the electorate for the House of Councilors election in the summer of 2016 after the voting age was lowered from 20 to 18 to encourage political participation by young people.