Valorie Rice, Senior Business Information Specialist
Arizona is growing older, but then so are most states in the nation. In 2022, the percentage of the population in Arizona under 18 was 21.6%, which is now below that of the nation at 21.7%. The state has typically had a higher percentage of the population under the age of 18 than the U.S. Arizona ranked 27th out of all states and the District of Columbia in 2022. This is very different from ranking sixth in the nation, which is where Arizona was back in 2010 when more than a quarter of the state’s population was under the age of 18.
Nationally, the percentage of the population under 18 has steadily been shrinking. It was 25.6% in the 2000 Census, 24.0% in the 2010 Census, and down to 22.1% in the 2020 Census. The latest population estimates for 2022, released in December for the U.S. and states, include the voting age population (those 18 and over). From these data, we can infer the population under the age of 18 now stands at 21.7%. Exhibit 1 shows that not only has the percentage of the population under the age of 18 decreased for both the U.S. and Arizona, but that Arizona now has a slightly smaller percentage of a younger population than the nation.
Exhibit 1. Percent of Population Under Age 18, Arizona and U.S.
Utah remains the state with the largest share of its population under 18, but even that has been in decline. In the 2000 Census, 32.1% of the population in Utah was under 18, and in 2022, that figure is now 27.6%. Idaho and Texas have also ranked among the states with the largest share of the younger population between 2000 and 2020. The percent of younger people in New Mexico has steadily declined since 2000, going from 27.9% percent under age 18 in 2000 to 21.7% in 2022. In 2020, New Mexico was just above Arizona in rankings as the two states fell to 19 and 20. They fell again to 26 and 27 in 2022. Exhibit 2 reports the top 10 states by ranking for 2000 to 2022.
Exhibit 2. Top 10 States Ranked by Percent of Population Under Age 18, 2000-2022
New England states and the District of Columbia have consistently had the smallest percentage of the population under 18. The District of Columbia had the lowest percentage for the last three decennial censuses, as seen in Exhibit 3. Vermont had the smallest share in 2022 followed by Maine, New Hampshire, and the District of Columbia.
Exhibit 3. Bottom 5 States Ranked by Ranked by Percent of Population Under Age 18, 2000-2022
Even though the District of Columbia ranks low, it actually had an increase in its younger population since the 2020 Census. The overall population for the District of Columbia decreased by 2.6% between 2020 and 2022, while the under age 18 population grew by 8.8%. Arizona, however, had an overall population growth of 2.9% as the population under 18 decreased by 1.3% during that time. States with the largest increase in the percent of the population under 18 over the last two years were Texas at 2.4%, Florida at 2.3%, and South Carolina at 1.3%. Wyoming (-4.0%), New Mexico (-4.0%), and Colorado (-3.8%) had the steepest drop in the population under 18.
