Mortgage rates eased this week, as expectations for rapid economic growth were tempered by continued worries about the impacts of the European debt crisis and the potential impact of government spending cuts.

Rates on 30-year fixed-rate mortgages averaged 3.54 percent for the week ending March 21, down from 3.63 percent last week and 4.08 percent a year ago, Freddie Mac said in releasing the results of its latest Primary Mortgage Market Survey. Rates on 30-year fixed-rate loans hit a low in Freddie Mac records dating to 1971 of 3.31 percent during the week ending Nov. 21, 2012.

For 15-year fixed-rate mortgages, rates averaged 2.72 percent, down from 2.79 percent last week and 3.30 percent a year ago. Rates on 15-year fixed-rate loans hit a low in Freddie Mac records dating to 1991 of 2.63 percent during the week ending Nov. 21, 2012.

For five-year Treasury-indexed hybrid-rate mortgage (ARM) loans, rates averaged 2.61 percent, the same as last week and down from 2.96 percent last year. The average rate for the week ending today ties an all-time low in Freddie Mac records dating to 2005 last seen during the week ending Feb. 28.

Rates on one-year Treasury-indexed ARM loans averaged 2.63 percent, virtually unchanged from last week, but down from 2.84 percent a year ago. Rates on one-year ARM loans hit a low in records dating to 1984 of 2.52 percent during the week ending Dec. 20, 2012.