There are 1.1 million fewer children living in the U.S. today than there were at the start of the decade, according to an analysis of new Census data by the Brookings Institution's William Frey.
The big picture: The adult population grew by 8.8% in the 2010s. in the three previous decades, the child population increased. The past decade marks a pivotal moment as the U.S. ages and, as a result, family life is transformed — especially because Americans are waiting longer to have children and having fewer of them.
Between the lines: The child population also plummeted in the 1970s — when members of Generation X were kids — after the much larger Boomer generation aged into adulthood. But the child population steadily rose from then until the 2010s.
- Even after a numerical decline in the 1970s, children still made up 28% of the total 1980 population, according to the Federal Interagency Forum on Child and Family Statistics. In 2019, kids only made up 22% of the total population, according to the latest Census data.
- "This isn't the first decade of child population decline. But it ushers in a period when adult growth will continue to dwarf child growth as the population ages and proportionately fewer women are in their child bearing ages," Frey told Axios.
In the past decade, child populations declined in more states than they rose. But a handful of areas, like the West and South, have seen a surge of families and kids.
The drivers: Vermont, New Hampshire and Connecticut saw their child and teen populations plummet between 2010 and 2019 — an 11% to 12% decrease.
- Under-18s made up 22% of New Hampshire's population in 2010, but that figure fell to 18% in 2019. That was the biggest drop in kids' share of the population in any state, according to Axios' Census data analysis.
- California, the most populous state, saw the largest numerical decline of under-18-year-olds of any state. There were 400,000 fewer children and teenagers living in the state this year than there were nine years ago.
The other side: The District of Columbia and North Dakota saw their shares of children and teens spike during the decade — with a more than 20% increase for both areas, largely driven due to their small populations.
- Each added around 30,000 children since 2010, becoming the only two U.S. areas where under-18 population growth outpaced the rest of the population.
- North Dakota's booming oil-driven economy and its relatively high birth rates likely played a role.
- And while the growth rate for kids living in D.C. has steadily outpaced the growth of its adult population, under-18s still make up a smaller share of the district's population than any state.
States with the largest share of their populations under 18:
- Texas (3rd in 2010)
- Idaho (2nd in 2010)
- Nebraska (10th in 2010)
- Alaska (4th in 2010)
States with the smallest share of their populations under 18:
- New Hampshire (8th in 2010)
- Rhode Island (6th in 2010)
Go deeper: Americans are moving less