People aged 65 or over account for one-quarter of Japan's total population for the first time since statistics began in 1950, Nihon Keizai Shimbun reported on Wednesday.
The nation's working-age population, those aged 15-64, dipped below the 80-million mark for the first time in 32 years. Japan has a total population of 125 million.
Japan's Ministry of Internal Affairs and Communications releases statistics about the population every April based on data collected the previous October.
The country's working-age population decreased 1.17 million from a year earlier to 79.01 million, accounting for 62.1 percent of the total population. The figure has been falling since it hit its peak in 1995.
The number of senior citizens aged at least 65 increased 1.11 million to 31.90 million. Meanwhile, the number in the 0-14 age bracket reached 16.39 million, or 12.9 percent of the total population, the lowest ever.