U.S. college tuition is growing at the slowest pace in decades, following a nearly 400% rise over the past three decades that fueled middle class anxieties and a surge in student debt.

Tuition at college and graduate school—after scholarships and grants are factored in—rose 1.9% in the year through June, broadly in line with overall inflation, Labor Department figures show. By contrast from 1990 through last year, tuition grew an average 6% a year, more than double the rate of inflation. In that time, the average annual cost for a four-year private college, including living expenses, rose 161% to about $27,500, according to the College Board.

Some schools are offering more discounts and cutting prices.

Abundant supply is running up against demand constraints. The number of two-year and four-year colleges increased 33% between 1990 and 2012 to 4,726, Education Department data show. But college enrollment is down more than 4% from a peak in 2010, partly because a healthy job market means fewer people are going back to school to learn new skills.

Longer-running economic and demographic shifts also are at play. Lower birthrates and the aging of baby boomer children have reduced the pool of traditional college-age Americans. The number of new high-school graduates grew 18% between 2000 and 2010 but only 2% in the first seven years of this decade, Education Department data show.