data japan 2023Japan joined the OECD in 1964, becoming the Organisation’s 21st member country and its first from the Asia-Pacific region. it is one of 38 OECD Members. ... Key data and interactiveThe 2025 population density in Japan is 338 people per Km2 (875 people per mi2), calculated on a total land area of 364,555 Km2 (140,755 sq. miles). Largest Cities in Japan # City Name