About 57% of U.S. colleges offer student insurance plans.

Researchers at the U.S. Government Accountability Office have published that figure in a review of the state of college health insurance plans.

About 20% of college students are uninsured, 6% have Medicaid coverage or other public coverage, and 67% are members of employer-sponsored group plans, John Dicken, a GAO director, writes in a letter describing the GAO’s findings.

About 7% of college students have student insurance coverage or other private, non-group coverage, Dicken writes.

Annual premiums for the college plans range from $30 to $2,400, and maximum benefits range from $2,500 for each illness or injury to unlimited coverage, Dicken writes.

Typical student plans cost about $500 to $999 per year, and 60% limited coverage to a maximum of $2,500 to $50,000 per condition per lifetime.

Many of the plans also imposed tight “internal benefit limits,” such as a limit of $150 per condition per lifetime on use of ambulance services, or a $1,200 per condition per lifetime limit on outpatient services, Dicken writes.

“Low internal benefit limits can make it highly unlikely for enrollees’ coverage to meet the plan’s maximum benefit amount,” Dicken writes.

One plan reviewed had a maximum benefit of $50,000 per condition per lifetime and an internal benefit limit of $1,200 per condition per lifetime for all outpatient benefits, including coverage for emergency services and diagnostic services, Dicken writes.

“Under this plan, students who require extensive outpatient services to treat one condition (such as a chronic condition or serious illness like cancer) would be unlikely to ever meet the $50,000 per condition per lifetime maximum benefit amount,” Dicken writes.