Japan's population fell by a record 0.22 percent to 127.515 million as of last Oct. 1, while people aged 65 or older surpassed the 30 million mark for the first time, the government said Tuesday.
The figures are from a survey by the Internal Affairs and Communications Ministry.
The decline of 284,000 in the total population, which also included foreign nationals, was the largest of its kind since officials began compiling comparable data in 1950.
It was also the second year in a row that the population has fallen.
Ministry officials attributed the decline to the number of deaths exceeding births and a rise in the number of foreign residents who left Japan compared with those entering the nation because of the impact of the March 2011 earthquake and tsunami and the economic slump.
People aged 65 or older accounted for a record 24.1 percent of the total population.
The number of people in this age bracket rose by 1.04 million to 30.79 million partly because many of those born in the baby-boom years of 1947 to 1949 have turned 65 years in a telling sign that measures such as increased social welfare spending must be addressed swiftly.
Meanwhile, the number of people 14 and younger fell to a record low of 13 percent.
The population decreased in 40 of the 47 prefectures. Fukushima Prefecture, home of the crippled Fukushima No. 1 nuclear plant, suffered the worst decline at 1.41 percent.
Of the seven prefectures that posted gains, Okinawa topped the list with a 0.56 percent increase.
For the first time, the number of people aged 65 or older surpassed those aged below 14 in every prefecture.
Akita Prefecture had the highest percentage of people 65 and older at 30.7 percent, followed by Kochi at 30.1 percent and Shimane at 30.0 percent.