The population is spread out among 3.8 million square miles across 50 states, yet nearly one-third of Americans live in just three states: California, Texas and New York.

For decades, the total fertility rate in the United States has been below the replacement fertility rate—the level of fertility necessary for the current generation to replace itself.

Elon Musk shared a chart on X purportedly showing more than 398 million eligible numbers in the Social Security database.

Conversely, New York saw the largest population decline, losing 238,000 people (1.2 percent), followed by California (91,000—0.2 percent) and Illinois (89,000—0.7 percent). The United States ...

In the United States, during the 40 years from 1975 to 2015 ... prime-age adults—those roughly 25 to 59—who produce more than they consume (see Chart 1). As a population ages, the proportion of ...