More than 40% of Japan’s municipalities might eventually vanish due to a sharp population decline brought on by a chronically low birthrate, according to a study by a private group of experts.

The study released Wednesday by the Population Strategy Council (PSC) deems local municipalities that would likely see their population of women age 20 to 39 — the core childbearing age group — reduced by half between 2020 and 2050 as having a risk of disappearing.

Of 1,729 local municipalities nationwide, the study identified 744 with such a risk.