Since 1990, South Dakota's adult population has grown in its total share of the overall population, while the state's youth population has decreased proportionally.
Recently updated federal data shows that 18-64 year-olds comprised 60.1 percent of South Dakota's population in 2014, up from 56.8 percent in 1990 but down from a recent high of 60.9 percent in 2011.
That recent loss appears due to gains made by those 65 and older. That cohort has grown from 14.7 percent of the state's population in 1990 to 15.3 percent in 2014.
At the same time, the two children's cohorts measured by the U.S. Census for the Age category have shrunk. Children ages 0 to 4 years old have gone from 7.8 percent in 1990 to 7.1 percent in 2014. Those ages 5 to 17 years old have dropped from 20.7 percent in 1990 to 17.6 percent in 2014.
When looking at sheer numbers, the 18- to 64-year-olds trounce the other groups, having swelled 117,334 between 1990 and 2014, compared to increases of only 27,892 for those 65 and older, 6,106 for the 0- to 4-year-olds and 5,839 for the 5 - to 17-year-olds.
The oldest South Dakotans, those 85 and older, have been growing as a subset of the 65 and older cohort. The number of these most senior citizens increased from 13,343 in 1990 (1.9 percent of the statewide population) to 20,871 (2.4 percent) in 2014.
The statewide retirement-to-working-age ratio (the number of retirees divided by the number of working-age adults) indicates that retirees account for a growing percentage of the population. That ratio has risen from 23.6 percent in 2010 to 25.4 percent in 2014. This shift, however, reflects a return to levels seen twenty-five years ago when 25.9 percent of the population was of retirement age.
South Dakota's population gets whiter as it gets older, with 28.6 percent of the state's 0- to 4-year-olds being of color compared to 3.5 percent for those 85 and older and 5.8 percent for those 65 and older.