The number of Japanese aged 20, the legal marker for adulthood in the country, will stand at just over 1.2 million on New Year's Day, unchanged from a year earlier and equating to less than 1 percent of the population for the eighth straight year, a government estimate showed Sunday.
Among a total population of 126.7 million, new adults account for only 0.97 percent. Their number has been halved from its 1970 peak of 2.4 million, which was the highest figure since comparable data became available in 1968.
The National Institute of Population and Social Security Research predicted that the number of new adults will dwindle to 1.08 million in 2025.
Within Japan's shrinking population, the number of new adults has been declining since the mid-1990s after the "second baby boomers," who were born between 1971 and 1974, reached adulthood.
Of the 1.23 million new adults, 630,000 are men and 600,000 are women, according to statistics from the Ministry of Internal Affairs and Communications.
With 2018 being the Year of the Dog under the Chinese zodiac of 12 animal groups, the number of Japanese born in years of the dog total 9.76 million.
Notable figures born in dog years include baseball star Shohei Ohtani (1994), three-time Olympic women's wrestling champion Saori Yoshida (1982), and shogi master Yoshiharu Habu (1970).
Japan marks Coming of Age day on the second Monday of January.