Households headed by people aged at least 65 are projected to account for more than 30 percent of households in Japan's 47 prefectures by 2020, the National Institute of Population and Social Security Research has said.

The number of people aged 65 or older who live alone is expected to more than double from its 1995 level by 2020 in 34 prefectures, in eastern Japan in particular, said a report released Friday by the think tank affiliated with the Health and Welfare Ministry.

The institute made the estimates based on the 1995 national census and 1997 projections on future populations.