An estimated 42% of adult Japanese women may end up never having children, the Nikkei newspaper reported, citing a soon-to-be-published estimate by a government research group.

In a more optimistic scenario, a quarter of women born in 2005 may end up not having offspring. The midpoint estimate by Japan’s National Institute of Population and Social Security Research calls for a third of them not having children, the newspaper reported Wednesday.

Birthrates are a critical issue for Japan and other countries with rapidly aging populations. The island nation posted the fewest births in its recorded history last year, continuing a seven-year decline. With a smaller workforce and fewer taxpayers to sustain the world’s third-largest economy, Japan has become one of the world’s most indebted countries.

The percentage of childlessness is even higher for men, with as many as 50% never seen having children, according to the report, the Nikkei said.

--With assistance from Marika Katanuma.

(Updates to add chart. A previous version was corrected to add a dropped word in the second paragraph.)