"Whether or not that happens will depend on a number of factors, including what changes are made to the federal loan system and market and economic conditions," says Research Associate Courtney McSwain. "Private loans certainly are growing, and students are using private loans more, especially students pursuing professional degrees."

Some number-crunching reveals nearly a quarter of all students pursuing a professional degree have taken out a private loan, compared with 5% of all undergraduates and graduates. More than three-quarters of private loan borrowers also receive federal aid available through the Stafford loan program. "When we look at the overall pool of students taking out [private] loans, the majority of those students are undergraduates because the majority of the student population is undergraduate," McSwain says.

"But when you isolate among students in various levels, a greater percent of professional students take out private loans because costs are so high and the types of grants they can get are limited."