WASHINGTON (AP) _ The average interest rate on 30-year fixed-rate mortgages averaged 6.83 percent this week, up from 6.79 percent last week, Freddie Mac, the mortgage company, said Thursday.

It was the 31st consecutive week that the average remained below 7 percent. It reached a 31-year low of 6.49 percent in early October. Its peak for 1998 was 7.22 percent in late April. Economists expect it to remain low this year.

Fifteen-year mortgages, a popular option for refinancing, averaged 6.48 percent this week, up from 6.43 percent.

On one-year adjustable-rate mortgages, lenders were asking an average initial rate of 5.61 percent, the same as the previous week.

The rates do not include add-on fees known as points.