Japan's population was an estimated 127.619 million as of Oct. 1, up 184,000 from a year earlier, with a record 19 percent aged 65 or older.
The Public Management, Home Affairs, Posts and Telecommunications Ministry said Friday the number of Japanese aged 65 and older rose 683,000 to 24.311 million, while the number aged under 65 fell.
The figures are based on estimates from calculations in the 2000 census and other data.
By age, those under 15 totaled 17.905 million, down 197,000, and the working-age population -- those aged between 15 and 64 -- totaled 85,404,000, down 302,000.
The number of males stood at 62.304 million, and females numbered 65.315 million.
There were 1.139 million births in the year to Oct. 1, down 37,000, and 1.023 million deaths, up 43,000.
Twenty-eight prefectures saw their populations fall from a year earlier. Akita had the largest drop, at 0.75 percent, followed by Wakayama at 0.53 percent and Aomori at 0.49 percent. Okinawa had the highest increase, at 0.76 percent.