The Federal Reserve reports that there are 12 million student loan borrowers between the ages of 30 and 39 and together, these graduates hold a collective $408.4 billion dollars in debt. That means that Americans in their 30s with student loan debt each have an average balance of $34,033.

Student debt is something we picture 20-year-olds dealing with while they live in their parents' basements. What may surprise you is that the average borrower in their 30s actually owes more than the average borrower in their 20s.

If you went to college in the United States, student debt is likely a big part of your financial report card. Approximately 70 percent of grads leave college with student debt, and over 44 million Americans hold a total of $1.4 trillion in student loan debt .

There are 17 million 20-year-olds with student debt . This larger pool of debtors holds $376.3 billion in debt — so the average American in their 20s owes an average of $22,135.

One possible explanation for thirty-somethings holding a disproportionate amount of debt is that they graduated into uniquely difficult times. Many left college at the height of the great recession, and faced elevated unemployment rates that forced many to default on or defer payment of their loans.

And in order to ride out the recession, many new graduates chose to pursue further education and take on even more debt. Sandy Baum, co-author of "Student Debt: Who Borrows Most? What Lies Ahead" explained to U.S. News & World Report that graduate students hold a disproportionate amount of debt.

"People think of student debt as an undergraduate problem, but it's really graduate students," she says.

Undergraduate students are able to borrow up to $5,550 per year in federal student loans. Graduate students, however, can borrow up to the full cost of attendance. Because there is no limit on borrowing for graduate school, students tend to take out large sums to attain these degrees.

A 2014 study by the Brookings Institute states that "roughly one-quarter of the increase in student debt since 1989 can be directly attributed to Americans obtaining more education, especially graduate degrees." Their research found that since 1989, the average amount borrowed to finance a graduate degree quadrupled, from approximately $10,000 to over $40,000.

To make things even more difficult, financially, is the fact that many in their 30s are now parents as well. The price of raising a kid in 2017? $233,610.

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