This includes people like Larry Perrone.

His journey into the legal profession started at the private Florida Coastal School of Law in Jacksonville, Florida. He had been working as a bartender and planned to borrow around $130,000, figuring he could make $80,000 a year as a lawyer at a private practice.

Perrone did well in his studies, and after a year and a half transferred to the more expensive William & Mary School of Law in Williamsburg, Virginia. That meant more borrowing, but potentially a lifetime of higher earnings because his degree would be stamped by a much more prestigious school.

"If you're going to get a tattoo, do you go to a really expensive place or to a cheap guy? It wasn't a really difficult decision for me," Perrone said.

In 2008 after graduating nearly $200,000 in the red, he took a job at a big firm in Washington, making $160,000 a year. "It worked out well." He initially put off buying a home, but finished paying his loans this year and is now eyeing a condo in Florida.

The Wow Feature

Perrone's story is part of a larger trend in which heavy borrowing is increasingly rewarded with big salaries. Seen another way, as the salaries of the well-educated have grown relative to everyone else over the last quarter century, so has the borrowing that has paid for their training.

By last year, the top fifth of total households by income, or those making more than $101,000, was on the hook for roughly a third of student loan balances, nearly twice their share in 1989, according to the Fed survey. At the beginning of the period, student loans were mostly held by middle income families -- the next two fifths down the income ladder. But their share fell sharply by 2013 and the share of the bottom two fifths held about steady.