United States - Population Ages 15 to 64 for Least Developed Countries was 57.59354 % of Total in January of 2020, according to the United States Federal Reserve. Historically, United States - Population Ages 15 to 64 for Least Developed Countries reached a record high of 57.59354 in January of 2020 and a record low of 51.98388 in January of 1983. Trading Economics provides the current actual value, an historical data chart and related indicators for United States - Population Ages 15 to 64 for Least Developed Countries - last updated from the United States Federal Reserve on April of 2024.