MCLEAN, Va., Dec. 28 (UPI) -- Thirty-year U.S. mortgage rates rose for the second week in a row but were still lower than this week last year, a mortgage report said Thursday.

Fixed-rate 30-year mortgages averaged 6.18 percent this week, up slightly from 6.13 percent last week but down from 6.22 percent a year ago, said the Federal Home Loan Mortgage Corp. (OTCPK:FREJO), better known as Freddie Mac. (NYSE:FRE)

"We expect to see continued volatility in housing market data even if mortgage rates stabilize," Freddie Mac Chief Economist Frank Nothaft said.

Rates on 15-year fixed-rate mortgages, often used in refinancing, averaged 5.93 percent, also up from last week's 5.89 percent average.

A year ago, the 15-year fixed-rate mortgage averaged 5.76 percent.

For five-year adjustable mortgages, rates also went up, rising to 5.96 percent this week, compared with 5.92 percent last week.

Rates on one-year adjustable-rate mortgages edged down to 5.44 percent this week from 5.45 percent last week.