SIOUX FALLS, S.D. (AP) — National American University is closing its Sioux Falls and Rapid City campuses as well as others as the school transitions to online classes.

The for-profit university attributes the campus closures to a steep decline in revenue and shifting student preferences. NAU President Ronald Shape says the university leases all of its locations, which adds to the ongoing costs of supporting an educational model that doesn’t fit today’s preferences.

The Argus Leader says combined revenue from tuition and other sources was down 24 percent year-over-year in the second quarter of the company’s current fiscal year. NAU campuses that have already closed include locations in Watertown and Rochester and Minnetonka, Minnesota.