Borrowers on the hook for more than half of student loans are delaying principal and interest payments, contributing to rising balances for recent graduates who face a weak jobs market, according to a new study.

“With unemployment rates remaining high, the repayment of these loans remains a concern,” said Ezra Becker, vice president of research and consulting for Chicago-based TransUnion, which conducted the study. “Students can defer their loans for only a certain period, often up to three years, and after that these students can find themselves in a difficult position financially.”

Filing for bankruptcy after that rarely solves the problem, as student loans generally aren’t dischargeable in court. So graduates have to either begin paying or ask for forbearance, another grace period that that buys them more time but for which some lenders also charge a monthly fee.

TransUnion, one of three major credit-reporting agencies, examined every active student loan in its credit database from March 2007 to March 2012, determining whether they were being repaid or were in deferred status — meaning repayment of principal and interest was temporarily delayed. It determined that 65.5 million of 128.8 million student loans outstanding as of last March were deferred. TransUnion said “virtually every student lender,” including the U.S. government, reports its data to the company.

The average debt per borrower rose, by 30 percent since 2007, to $23,829, TransUnion said.

And the graduates and the lenders aren’t the only ones affected. Rising student debt levels can act as a drag on the economy.

“Too many Americans are carrying around mortgage-sized student loan debt that forces them to put off major life decisions like buying a home or starting a family,” U.S. Sen. Dick Durbin, D-Ill., said in January after reintroducing two pieces of legislation related to student loans. “And it’s not only young people facing this crisis but also parents, siblings and even grandparents who co-signed private loans long ago.”

The U.S. Consumer Financial Protection Bureau said in an October report that “many recent graduates are seeking to pay less in interest on private and federal student loans so they can one day purchase a home or otherwise economically progress.”

“There are also signs that young workers are not able to save enough in tax-deferred retirement plans,” Rohit Chopra, the bureau’s student-loan ombudsman, said at a congressional forum on student loans in August in Chicago.

Consider Sheila Uribe, 28. The Chicago resident has about $60,000 in student debt after earning a business degree from Elmhurst College in Elmhurst, Ill. And because she works full time, she can no longer defer her loan payments.

The married mother of two, who works as an administrative assistant at a suburban machinery company, received federal aid for her studies in 2003 but, needing more money, she began taking out private loans in 2005. She ultimately took out three private loans, with her mother co-signing one of them.

She graduated with $35,000 in student loan debt.

“When you’re young, the future seems a long way off, and loan repayments sound pretty manageable,” said Uribe, who said she has worked since she was 15 years old.