More people borrowing for education are failing to pay off their loans.

Almost a third of student-loan borrowers in repayment were delinquent at the end of last year, up from about a quarter in 2008 and 20 percent in 2004, according to a report on household debt and credit Thursday by the Federal Reserve Bank of New York.

The amount of educational debt, which includes federally backed and private loans taken out by students and parents, has almost tripled in the past eight years to $966 billion, the bank said. With costs to attend college continuing to outpace the inflation rate, more borrowers are struggling to pay. That makes it harder for people -- especially those between 25 and 30 -- to secure other types of credit, including home mortgages.

“Student loan debt is the only kind of household debt that continued to rise during the Great Recession and has now the second-largest balance after mortgage debt,” wrote Donghoon Lee, an economist at the New York Fed. “With delinquent student debt, mortgage origination is very difficult. The mortgage origination gap across the size of student debt has declined between 2005 and 2012.”

The New York Fed report is based on a sample of data provided by the Equifax Inc. credit bureau, and examines borrowers’ current debt. It doesn’t measure how much was taken out at origination.

About 44 percent of student loan borrowers aren’t repaying their loans, because of deferments, forbearances or they are still in school.

Younger Borrowers

Delinquency rates in 2012 were highest among borrowers under the age of 30 who are repaying their loans. Thirty-five percent were 90 or more days behind, compared with 21 percent in 2004.

The Fed also reports on the share of all borrowers who are delinquent for 90 days or more, including those in deferral, forbearance or still in school. That rate is 16 percent for those under 30, up from almost 8 percent in 2004.

As more people attend college, the average educational loan balance, as well as the numbers of borrowers and delinquencies are increasing. The number of student-loan borrowers was almost 39 million in 2012, up 70 percent from about 23 million in 2004. The average balance in 2012 per borrower was $24,700 compared with $15,308 eight years earlier.

Total student-loan debt in the fourth quarter was $966 billion, up $10 billion from the previous quarter, according to the New York Fed. The federal Consumer Financial Protection Bureau put the number at $1 trillion last year.

‘Stay Afloat’

Ryann Roberts, 22, is one of those borrowers and has seen friends struggle with their debt as a large share of monthly expenses.

She is deferring on more than $37,000 in loans for an undergraduate degree in health policy at Carnegie Mellon University in Pittsburgh and for the first year of a two-year master’s in public health at George Washington University. She has kept her graduate costs low by working full-time as an administrator at the university’s medical school, which waives some tuition for employees.

“I’m worried about graduating and making enough money to pay the loan back and stay afloat,” Roberts said.