(Bloomberg News) Borrowers defaulted on federal student loans at an 8.8 percent rate for fiscal 2009, up from 7 percent a year earlier, the U.S. Education Department said today.

The statistic covers borrowers whose first loan repayments were due during the year that ended Sept. 30, 2009, and who had defaulted by Sept. 30, 2010. About 320,000 out of 3.6 million borrowers in that group were in default, which the department defines as being at least 270 days late on a payment. The official 2009 rate fell slightly from an 8.9 percent estimate released in May.

The rate at for-profit colleges, such as University of Phoenix owner Apollo Group Inc., rose to 15 percent in fiscal 2009 from 11.6 percent a year earlier.

"Borrowers are struggling in the economy," Education Deputy Undersecretary James Kvaal told reporters on a conference call. "We do see a strong relationship between student loan default rates and unemployment rates."

Growth in for-profit colleges, which had disproportionately high default rates, also contributed to the trend, Kvaal said.

Default rates among students at for-profit colleges have led the Obama administration to increase regulation and Congress and state attorneys general to conduct investigations.

The 2009 rate was the highest since an 8.8 default rate in 1997. The rate peaked at 22.4 percent in 1990.

Borrowers attending for-profit colleges defaulted at more than twice the 7.2 percent rate for those at public colleges and three times the 4.6 percent rate at private nonprofit institutions, according to the Education Department.