“Since 2004, student loan balances have more than tripled, at an average annualized growth rate of about 13 percent per year, to nearly $1.2 trillion, in 2014.”

Meta Brown, Andrew Haughwout, Donghoon Lee, Joelle Scally, and Wilbert van der Klaauw:

Our data indicate that both increased numbers of borrowers and larger balances per borrower are contributing to the rapid expansion in student loans. Between 2004 and 2014, we saw a 74 percent increase in average balances and a 92 percent increase in the number of borrowers. Now there are 43 million borrowers, up from 42 million borrowers at the end of 2013, with an average balance per borrower of about $27,000.

The heterogeneity of borrower indebtedness is very pronounced. As shown in the chart below, nearly 39 percent of borrowers owe less than $10,000, and the median balance is about $14,000. At the high end, more than 4 percent of borrowers, about 1.8 million people, owe more than $100,000.