Tokyo 2024 Population Census. The total population of japan in 1945 was about 71 million. These prefectures account for 37.7 percent of the total population.

These prefectures account for 37.7 percent of the total population. The cohort of people aged 65 years and older consisted of around 36.5 million people in 2022 and was estimated to make up over 38 percent of the population by 2070.