Japan's capital is still one of the most populous cities in the world, but according to Ministry of Internal Affairs and Communications data [PDF], the country has seen its first population decline since the 5-year census was first recorded in 1920.

A graph created by Bloomberg shows Japan's population growing from the 1920s and continuing on that arc until around 2010. Five years later, the 2015 population was at 127.1 million, a 0.7 percent drop from the last census.

While the populations of Tokyo and Okinawa rose by 2.7 and 3 percent, respectively, the pattern didn't continue in other parts of the country, Japan Today reports. Population decreased in 39 of Japan's 47 prefectures (districts divided for local government).

Why the decline? Experts point to low birth rates, as well as the fact that Japan is aging, with an estimated 27 percent of the population now over 65. Still, The Washington Post points out that Japan's woes are not exclusive—the U.N. predicts that 48 countries will see population slides by 2050.

[h/t Bloomberg]