While noting progress in areas such as student preparation, the biennial study by the National Center for Public Policy and Higher Education drops the country to an “F” in affordability from the “D” it received in the nonprofit group’s report two years ago.

Among individual states, only California, Utah and Minnesota earned higher than a “D.” California still had the top grade of any state, but its “A” from 2002 fell to a “B” in the latest report after sharp tuition increases.

The report card evaluates states on the performance of their private and public four-year schools and community colleges in five categories, with grades ranging from A to F.

On affordability, the report card contradicts some recent studies that argue increases in financial aid have kept pace with recent tuition hikes, so real college costs have stabilized.

The report card, titled “Measuring Up 2004,” grades affordability in part by comparing net college costs with the average family income in each state. By that measure, the study claims, college is becoming less affordable in most states.

David Breneman, dean of the Curry School of Education at the University of Virginia and an adviser on the report, said the combination of higher prices and a population boom among college-age people is likely to bump students from four-year colleges to more affordable community colleges, and from community colleges out of the system.

“For at least another five to eight years we’re looking at a real denial of opportunity,” he said.