Japanese women are expected to live more than 86 years, topping the world longevity ratings for the 25th straight year, the government reported Monday.

The statistics for 2009 compiled and published by the Ministry of Health, Labor and Welfare showed both Japanese women and men extended their average life expectancy to new records — 86.44 years for women and 79.59 years for men. Average life spans rose by almost five months for women and nearly four months for men compared to the previous year.

Japanese men, however, saw their average life expectancy slip to fifth from fourth in the world ranking, according to a ministry official, who spoke on condition of anonymity, citing department rules.

Long life is usually good news. But in a country with a low birth rate and declining population, longer life expectancies mean a disproportionately large elderly population. The graying of society is expected in the near future to strain government services and pension programs, while causing labor shortages.