South Dakota Adults Grow in Population, Youth Stagnates
According to the US Census Bureau, the overall South Dakota population continues to age, and the trend shows no sign of reversing in the near future. Since 1990 the adult population between the ages of 18 and 64 has increased from 56.8% of the overall population to 59.3% in 2016. Additionally, the fraction of adults aged 65 and older has grown from 14.7% of the state's population in 1990 to 16.0% in 2016.
At the same time, the US Census Bureau reports that the relative number of younger South Dakotans has declined. Children between the ages of 0 and 4 years old have gone from 7.8% of the population in 1990 to 7.1% in 2016. Similarly, the fraction of children between the ages of 5 and 17 years old has dropped from 20.7% in 1990 to 17.6% in 2016.
When looking at sheer numbers, the 18- to 64-year-olds trounce the other groups, increasing by 118,151 between 1990 and 2016, compared to increases of only 36,474 for those 65 and older, 6,865 for the 0- to 4-year-olds and 7,960 for the 5- to 17-year-olds.
The overall aging trend in the state is due to the aging of the “baby-boomer” generation, and nowhere is this more evident than in the growing number of senior citizens in the state. 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 19,226 in 2010 (2.4% of the statewide population) to 21,516 (or 2.5 percent) in 2016.
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. The statewide retirement-to-working-age ratio has risen from 23.6% in 2010 to 27.0% in 2016. This ratio is even more pronounced in the Black Hills region, where the ratio was 28.9% in 2016—a substantial increase over the 22.7% ratio in 2010.
While the state as a whole appears to be aging, Census data indicates that some counties are much greyer than others. With a median age of 54.2, Custer County had the Rushmore State’s oldest residents in 2016. In contrast, Todd County had the state’s youngest population with a median age of 24.4. The chart below shows the three oldest and youngest counties in the state.