Japan's population stood at 128,057,352 as of Oct. 1, 2010, up 0.2 percent from five years earlier, marking the slowest growth since the once-in-five-years census began in 1920, the final results of the survey showed Wednesday.
When non-Japanese residents are excluded, the population dropped by about 371,000, or 0.3 percent, decreasing for the first time since 1975, when it began compiling the population of Japanese citizens separately from non-Japanese, the Internal Affairs and Communications Ministry said.
"While Japan has entered an era of population decline, its total population has been flat because of an increase in foreign nationals," a ministry official said.
The number of non-Japanese residents rose 5.9 percent, or about 93,000.
Japan remains the 10th most populous nation, accounting for 1.9 percent of the world's population, according to a U.N. population estimate for 2010.
The male population stood at 62,327,737, while the female population came to 65,729,615.
Those aged 65 or older numbered about 29,246,000, accounting for 23.0 percent of the total population, up from 20.2 percent in the previous census. The country's graying trend stayed at the top level in the world, surpassing Germany and Italy.
In contrast, those below 15 accounted for 13.2 percent of the population, down 0.6 percentage point, confirming that the population of the young is shrinking as the country grays rapidly.
The number of households rose 4.8 percent from 2005 to 51,950,504, topping the 50 million mark for the first time ever, but the average number of members per household hit an all-time low of 2.42, the report showed.
The number of single-member households stood at around 16,785,000, comprising more than 30 percent of the total households for the first time.
Of Japan's 47 prefectures, population increased only in nine -- including Tokyo and Okinawa -- while it declined in the rest. Six prefectures -- Tochigi, Shizuoka, Mie, Kyoto, Hyogo and Okayama -- saw their population growth turn negative.
At the municipal level, population decreased in 1,321 cities, towns and villages, or 76.4 percent of all the country's municipalities.