NEW YORK (CNNMoney.com) -- NEW YORK (CNNMoney.com) -- Mortgage rates slipped for the sixth straight week on continued signs of weakness in the housing sector and declining consumer confidence, Freddie Mac reported Thursday.

The average rate on 30-year fixed-rate loans fell to 6.44 percent for the week ending Aug. 31 from 6.48 percent the week before.

A year ago, the 30-year mortgage rate averaged 5.71 percent. The last time the 30-year rate was this low was the week of April 6, 2006.

"Mortgage rates continued to drift lower this week in large part because of the cooling in the housing market and in consumer confidence, thus giving financial markets reason to believe that economic growth will moderate and inflation will remain in check," Frank Nothaft, Freddie Mac vice president and chief economist, said in prepared statement.

"By some indicators, personal incomes are growing faster than the cost of housing. Combined with the still historically low mortgage rates, this will help to support the housing industry as it levels off from the record highs of the last few years," said Nothaft.

Freddie Mac said the 15-year rate slipped to 6.14 percent from the previous week average of 6.18 percent. A year ago, the 15-year rate averaged 5.32 percent.

The last time the 15-year rate was this low was the week of April 6, 2006.

Five-year adjustable-rate mortgages fell to 6.11 percent from 6.14 percent last week.

The five-year ARM averaged 5.30 percent a year ago.

The average one-year adjustable-rate mortgage fell to 5.59 percent from 5.60 percent the previous week. At this time last year, the loan averaged 4.48 percent.

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