https://upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Russian_population_%28demographic%29_pyramid_%28structure%29_on_January%2C_1st%2C_2022.png/1280px-Russian_population_%28demographic%29_pyramid_%28structure%29_on_January%2C_1st%2C_2022.png
https://ja.m.wikipedia.org/wiki/%E3%83%AD%E3%82%B7%E3%82%A2%E3%81%AE%E4%BA%BA%E5%8F%A3%E7%B5%B1%E8%A8%88
