The World Without Children #infographic

As of 2012, children ages 0 to 19 make up 23 percent of the U.S. population, down from a peak of 36 percent at the end of the "baby boom" in 1964, according to the forum on Child and Family Statistics. Children's share of the population is projected to continue its gradual decline through 2050, when they're likely to make up only 21 percent of the population.