In 2021, 81.2 million Americans were under the age of 20. That’s about 1.5 million more than in 2000. However, the overall population grew by nearly 50 million people, meaning that young people accounted for a smaller share of the population in 2020.
The share of young people in the US has decreased since the 1970s, though much of the decline occurred between 1970 and 1990, when the baby boom generation grew up.
