A student loan bubble

Sarah Jaffe suggests that the U.S. might have one:

According to the National Center for Education Statistics, college enrollment skyrocketed 38 percent, from 14.8 million to 20.4 million, between 1999 and 2009. (The previous decade it had only gone up 9 percent.) This should be a good thing—except it was not accompanied by measures to make tuition affordable for working families who wanted to send their kids to school. Combined with the decline in the type of union manufacturing jobs that used to allow workers to be comfortably middle-class without a college degree, we've wound up with working-class families taking on debt to send their kids to college, which they are told will help those kids make more money.