The estimated number of children under 15 in Japan as of April 1 fell by 350,000 from a year before to 13.66 million, down for the 44th consecutive year, the internal affairs ministry said Sunday.

The country's child population hit the lowest level since comparable data became available in 1950. The ministry released the data a day before Children's Day on Monday.

The number of boys stood at 6.99 million, and that of girls 6.66 million.

The proportion of children in the country's overall population came to a record low of 11.1%, dropping for 51 years in a row.

According to United Nations and other estimates with different survey periods, Japan had the second-lowest share of children in the total population among 37 countries with a population of more than 40 million. South Korea had the lowest share, at 10.6%.

The latest ministry data showed that the number of children between ages 12 and 14 stood at 3.14 million in Japan, followed by those between ages 9 and 11 at 3.02 million, those between ages 6 and 8 at 2.78 million, those between ages 3 and 5 at 2.5 million, and those between ages 0 and 2, at 2.22 million.

According to data as of Oct. 1 last year, all 47 prefectures logged year-on-year decreases in child population. Only Tokyo and Kanagawa Prefecture had child populations of over 1 million.

Also by prefecture, Okinawa had the highest proportion of children, at 15.8%, followed by Shiga and Saga, each at 12.7%.

The lowest share was 8.8%, in Akita, followed by Aomori, at 9.8%, and Hokkaido, at 9.9%.