NEW YORK (CNNMoney) -- When they should be worrying about affording retirement, a growing number of senior citizens are drowning in student loan debt instead.
Between 2005 and 2013, student loan debt among seniors 65 and older rose by more than 600% from $2.8 billion to $18 billion, according to a new report from the Government Accountability Office.
Out of all student debt holders, seniors still account for a small percentage. But their ranks are growing rapidly -- quadrupling in size since 2004 to 706,000 households.
While the majority of debt, about 80%, owed by seniors comes from loans taken out to fund their own college educations, 20% of loans were taken out for a child or dependent, according to the GAO report.
At age 57, Rosemary Anderson is approaching retirement age with $152,000 in student loan debt.
Twenty years ago, she took out $65,000 in loans in order to pay for her bachelor's and master's degrees. But after getting divorced, losing her job and caring for her sick brother, she basically gave up on making payments. She was hit hard by interest and penalties and the amount she owes has since climbed by tens of thousands of dollars.
CNNMoney profiled Anderson last month, and she testified at a congressional hearing about older Americans with student debt on Wednesday.
\"I will be indebted for life,\" Anderson said in her testimony. \"I find it very ironic that I incurred this debt as a way to improve my life, and yet I sit here today because the debt has become my undoing.\"
Default rates have also been rising with a debtor's age, the report found. While only 12% of federal student loans belonging to people ages 25 to 49 were in default in 2013, that rate spiked to 27% for Americans between 65 and 74 years old, and to more than 50% for people 75 and older.
Failing to pay back these loans can have dire consequences. Lenders will even take a bite out of Social Security payments to get the money they're owed.
Last year, 156,000 Americans had their Social Security benefits garnished because they had student loans that were in default, according to analysis conducted by the U.S. Treasury for CNNMoney. That's triple the 47,500 people who had payments garnished in 2006.
\"Some may think of student loan debt as just a young person's problem,\" said Senate Special Committee on Aging Chairman Bill Nelson. \"Well, as it turns out, that's increasingly not the case.\"