McLEAN, Va. -- The average rate for 30-year fixed-rate mortgages has hit a six-month high.

According to Freddie Mac, the rate jumped to 5.98 percent this week from last week's average of 5.91 percent.

That was the highest the 30-year has been since the end of March, when it averaged 6.04 percent.

A year ago, it stood at 5.82 percent.

A competing survey from Bankrate.com had the average 30-year fixed-rate mortgage jumping from 5.97 percent to 6.07 percent.

Frank Nothaft, chief economist for Freddie Mac, said inflation jitters, caused in part by extended high energy costs, are responsible for the increases.

Nothaft said he believed mortgage rates would continue to rise in coming months as the economy keeps growing but at "perhaps a slightly slower pace than in the recent past."

The average for the 15-year fixed-rate mortgage, which is popular for refinancing, was 5.54 percent -- up from 5.48 percent last week.