While revenue generated by athletics continues to rise, it is being outpaced by expenses, according to an NCAA study of athletic department budgets in 2013.

The report found that expenses exceeded revenue at all but 20 schools in the Football Bowl Subdivision. The average loss among the Power 5 conferences was $2.3 million. At all other FBS schools, it was $17.6 million.

The report did not specify which 20 FBS athletic departments had higher revenues than expenses.

Median annual revenue generated through ticket sales, broadcast agreements and other sources increased by 3.2 percent from 2012 to 2013, the study found, while median total expenses rose by 10.6 percent.

At schools where the athletic revenue does not meet expenses, institutional subsidies are used to bridge the gap. But the report found that at the median Division I school, the athletics budget rose more quickly than the institutional budget, as well.

"If the trend of athletic spending outpacing institutional spending continues, institutions will need to be able to justify that spending to the university community and the general public," said NCAA Chief Financial Officer Kathleen McNeely. "The value that athletics brings to campus life, life-long connection to alumni, and enhancing diversity on campus are all important outcomes from athletic programs that need to be celebrated and shared."

Athletic spending and revenue was part of the testimony in the Ed O'Bannon class-action suit heard in June, where a judge ruled that the NCAA's rules barring athletes from being compensated for the use of their names, images and likenesses violated antitrust laws.

Conference USA Commissioner Britton Banowsky testified during the trial that none of his conference's programs are self-sustaining financially and the shortfalls have to be made up with subsidies and, occasionally, student fees. He suggested some schools might consider dropping football if forced to share revenue with athletes for their name, image and likeness rights.

A large chunk of the expenses at many major programs is eaten up by coaching salaries and facilities upgrades. Coaching salaries continue to rise, with a handful of top FBS coaches making $5 million a year or more -- topped by the $6.9 million a year earned by Alabama's Nick Saban.

The SEC announced Wednesday that all 14 of its schools had "taken steps to enhance the fan experience" for game days, including major stadium renovations at LSU, Texas A&M and Mississippi State.

The NCAA study found that Football Championship Subdivision Schools bucked the trend in Division I, reporting a 10.1 percent increase in generated revenues since 2012 and only an 8 percent increase in expenses.

The report also studied athletics budgets at Division II and Division III schools separately and found that revenues failed to exceed expenses at every school on those levels.