The number of older Americans taking on student debt on behalf of their children and grandchildren has quadrupled in the past decade, with consumers 60 and older now holding $66.7 billion in student loan debt, according to a new report by the Consumer Financial Protection Bureau.

The skyrocketing cost of college has placed a particular burden on older Americans, many of whom are struggling to pay back growing debts in their retirement years, the report said. Nearly 40 percent of federal student loan borrowers 65 and older are in default, the highest rate for any age group, the data shows.

RETIREMENT AT RISK

“Student loan debt is clearly an intergenerational problem, and what we’re seeing is that this is unfortunately putting older consumers’ retirement at risk,” said Seth Frotman, assistant director of the CFPB’s office for students. “Older Americans are struggling under the weight of student loan debt.”

Americans owe nearly $1.4 trillion in outstanding student loans. A slow job-market recovery, growing income inequality and stagnant wages have made it difficult for younger Americans to be economically independent, and there are signs that those financial struggles are dragging down their parents and grandparents as well.

“A large portion of older student loan borrowers struggle to afford basic needs,” the report said, adding that older borrowers were increasingly likely to have skipped necessary doctors’ appointments and prescription medications because they couldn’t afford them.

SOCIAL SECURITY SEIZED

A growing number of borrowers 65 and older also said that their Social Security benefits – often the only source of regular retirement income for older Americans – had been seized because of unpaid student loans, according to the report. Those with student loan debt also had less money saved for retirement than did their counterparts without student loan debt.

The escalating cost of college – and the insurmountable debts that follow – were hot-button issues during last year’s presidential campaign. Democratic primary candidate Bernie Sanders won the support of millions of millennials in part by promising to offer free tuition at all state colleges and universities.

For his part, President-elect Donald Trump has said he will reduce the burden on borrowers by capping federal student loan payments at 12.5 percent of their income. After 15 years, their debts could be forgiven entirely, he said in an October speech in Ohio.

“Students should not be asked to pay more on their loans than they can afford,” he said. “The debt should not be an albatross around their necks for the rest of their lives.”

While Americans between ages 18 and 39 continue to hold most of the country’s student loan debt, older Americans are increasingly affected. A record 2.8 million Americans over 60 had outstanding student loans in 2015, up from 700,000 in 2005, the report said.

Older Americans are also taking on larger swaths of student debt – the average borrower over 60 now owes $23,500 in student loans, nearly double the $12,100 they did a decade earlier, the report said. On top of that, many also have mortgages, auto loans and medical debt.

ON FIXED INCOME

“When you’re retired, you’re on a fixed income, and there are so many things that could go wrong – your house could get a leaky roof, you might need medical care – and it becomes very difficult for people to balance all of those expenses,” said Maggie Flowers, associate director of economic security at the National Council on Aging in Arlington, Virginia.