South Dakota's population below age 20 has shrunk as a percentage of the total population in recent decades, but that trend appears to have stabilized, according to recently updated federal data.
At the same time, the nation's youth population continues a slow decline as a proportion of the overall population.
In South Dakota in 2014, those 19 and younger comprised 24.7 percent of the total population—the same as in 2013, compared to 28.5 percent in 1990 and 26.8 percent in 2000. The state's youth population slid from 24.9 percent in 2010 to 24.6 percent in 2012 before making a slight rebound.
Nationwide, those 19 and younger made up 23.1 percent of the total population in 2014, down from 23.3 percent in 2013 and from 25.7 percent in 2000.
The number of South Dakotans younger than 20 was nearly 12,000 more in 2014 than in 1990 — 210,407 compared to 198,462. At the same time, the number of adult South Dakotans grew by more than 145,000, from 497,542 to 642,768.
As a proportion of the state's population, South Dakota children ages 10-14 have dropped the most, going from 8 percent in 1990 to 6.5 percent in 2014. That cohort is followed closely by children ages 5 to 9, who slid from 8.4 percent to 7 percent of the total population. South Dakotans ages 0 to 4 went from 7.8 percent in 1990 to 7.1 percent in 2014, while those ages 15 to 19 went from 7.3 percent to 6.8 percent.
In 2000, the 15 to 19 age group had the largest share of the overall population, at 8.3 percent. By 2010, the 0 to 4 cohort had surpassed the teens, at 7.3 percent compared to 7.1 percent for the 15- to 19-year-olds. In 2012, the 5- to 9-year-olds rose to 7 percent to surpass the 15 to 19 group, which was at 6.9 percent that year.
By 2014, the 0 to 4 group—the smallest group in 2000—had become the largest group, at 7.1 percent. They were followed closely by the 5- to 9-year-olds at 6.9 percent, then by the 15 to 19 group, at 6.8 percent. The 10 to 14 age group, which was the second-largest group from 1990 through 2005, was the smallest in 2014 at 6.5 percent.
When looking at ages by single years, the ages 9, 10, 11 and 12 each had fewer people in 2014 than in 1990, and each age between 10 and 18 has fewer people than in 2000.
NOTE: The figures for South Dakota's adult population have been updated from the original online publication of this article. The initial numbers reflected the state's entire population, not only its adult population.