The national average for tuition at public four-year institutions jumped by $5,653—to $9,139 in 2014-15 from $3,486 in 1990-91. At public two-year institutions, the national average tuition increased by $1,692—to $3,347 from $1,655 during the same period.

 

The National Center for Public Policy and Higher Education discovered that for every $1,000 in tuition increase, enrollment among low income students drops 5 percent. "