College is becoming less and less affordable to more and more families higher and higher on the socioeconomic ladder.

As tuition and other fees have climbed and state funding of public institutions has failed to keep pace with rising costs and growing enrollment, a college education is being priced out of the reach of middle-class and even upper-middle-class families.

According to a recent report from researchers at the University of Pennsylvania and Vanderbilt University, families earning 48,001 to $75,000 a year had to pay a significant portion of their gross income to send a student to a public four-year nondoctoral institution. On average, it cost 16 percent (in Alaska) to 33 percent (in New Jersey) of their income in 2013, the latest year for which complete statistics were available for the report.

The burden was higher at public research universities, according to the report, “2016 College Affordability Diagnosis.” Families would have had to pay, on average, 17 percent (Wyoming) to 31 percent (Alabama) of their income to enroll in such state-run institutions as the University of Wyoming or the University of Alabama.