Tuitions and other costs have shot up Even counting the advent of aid, affording a four-year college education is one the biggest hurdles for middle-income families. "It now takes a higher percentage of family income to finance higher education," Baum said.

In 1976, average annual tuition, room and board cost an inflation-adjusted $6,863 at 4-year public schools and $14,105 at a private college, according to data from the National Center for Education Statistics.

By 2006, the sticker price had risen to $12,796 and $30,367 respectively, according to the College Board. The average net price - what families actually pay for college after subtracting grant aid and tax benefits - is lower ($9,696 at public schools and $21,367 at private colleges). But those out-of-pocket costs still exceed the total nut faced by parents in the 1970s.

Student debt has risen Of course, students shoulder a big portion of costs as well. At least two-thirds of college graduates today carry debt burdens into the first decade or more of their adult lives. The median debt load of college graduates ranges between $15,500 (at public universities) to $24,900 (at for-profit private schools), according to the College Board.

In addition, as many as 25 percent of college students are estimated to rely on credit cards to finance part of their college education.