I traveled around North Carolina in 2000 to write a series of articles about the future of the state’s renowned public university system. As I talked to parents, they often remarked how they didn’t really need to save much money to pay the tuition bills for their children. At the time, tuition and fees were about $2,000 a year at most of the universities across the University of North Carolina system.

Today, those same universities charge about $8,500 in tuition and fees. North Carolina parents and students were not alone in experiencing sticker shock over college tuition bills during the past decade. Across the country, the average price of a public four-year college in today’s dollars has increased by 13 percent since 2010, according to the College Board. That followed a 24 percent increase between 2005 and 2011.

Those rising tuition prices during the past 15 years coincided with falling incomes of American families. The percentage of households making more than $100,000 has been shrinking, while the proportion earning less than $35,000 has grown. As a result, as you can see in the chart below, the average sticker price of college now eats up more than 40 percent of a family’s paycheck. In 2001, it accounted for less than a quarter.

 Source: Bureau of Labor Statistics (BLS); IPEDS

Even if colleges and universities were able to freeze their tuition prices, the cost of a college degree for most Americans would feel like it’s continuing to rise.

That trend is likely to worsen for colleges and universities. “The students graduating from high school over the next decade are a less financially well-off group than the one that graduated in the last decade,” Jerry Lucido, executive director of the Center for Enrollment Research, Policy, and Practice at the University of California told me.

The fast-growing segment of today’s middle class are those 65 and older who pull in generous retirement benefits and often continue to work. Meanwhile, among those likely to have children going to college in the middle of next decade, family incomes are mostly shrinking. According to one analysis of Census data, of the 450 counties in the U.S. with significantly more younger than older children, all but 100 of them have median incomes below the national average.

Some of the biggest declines in middle-class households have occurred in the Northeast and Midwest, where industrial economies have collapsed. Those also happen to be regions that are home to the greatest concentration of colleges and universities. Researchers have found that less affluent students are most likely to go to college within 50 miles of home.

It’s no wonder then that campuses such as Mount St. Mary’s University in Maryland are struggling financially because families in their primary recruitment area increasingly can’t afford them.

Unfortunately, too many higher ed leaders remain in denial about the broader economic pressures facing their institutions. Some are waiting for relief from an economy that will return to the highs of the 1990s, or at least to the days before the Great Recession. Others are hoping for expanded government student aid programs ushered in with a new administration in 2017.

But the most likely scenario is the one staring them in the face: a student body that is much less affluent and less prepared academically for college than the one that propelled the expansion of higher education during the past two decades.