Student debt continues to grow, albeit more slowly than in previous years.

About 66 percent of college students graduated last year carrying debt. On average, they owed $28,650, according to an annual report on student loans by The Institute for College Access & Success.

The average debt per graduate rose just 1 percent in 2017 from the year prior. It spiked 4 percent a year on average between 1996 and 2012.

Although that deceleration is welcome news, it doesn't tell the whole story, said James Kvaal, president of TICAS.

"There are real reasons for concern about the crisis that is happening among certain groups of students," Kvaal said.

More from Personal Finance

How to safeguard your 529 plan right now

These colleges will allow you to bring your furry friends

This move can shave $1,000 off your student loan tab

There is currently a record high 8.9 million federal student loan borrowers in default, and another 1 million borrowers default each year, according to TICAS. Graduates from low-income families are five times as likely to default on their loans than their higher income counterparts. One in five black college graduates defaulted within 12 years of entering college, TICAS reports.

Kvaal attributes the slowdown in student-debt growth to the fact that net tuition has been growing more slowly as of late and that state spending on higher education has recently ticked up.

Student loan expert Mark Kantrowitz says students are simply hitting the federal student loan limits, and borrowing is shifting to parents. He calculates that parent student loan debt rose 20 percent between 2011 and 2016, from $27,000 to $33,000.

Average debt at graduation varies widely per state.