Mortgage rates hit record lows again this week, with the average conforming 30-year fixed mortgage rate inching lower to 4.74 percent, according to Bankrate.com's weekly national survey. The average 30-year fixed mortgage has an average of 0.39 discount and origination points.

The average 15-year fixed mortgage bucked the trend, rising slightly to 4.22 percent, while the larger jumbo 30-year fixed rate declined to a new low of 5.48 percent. Adjustable rate mortgages were lower as well, with the average 5-year ARM ticking down to 4.06 percent and the average 7-year ARM retreating to 4.46 percent.

Mortgage rates have fallen as a result of worries about the health of the economy, as investors have stampeded into the safety of Treasury securities. Mortgage rates are closely related to yields on long-term government debt. The lingering uncertainty about whether the economy gets better or worse from here will help keep rates at ultra-low levels, a boon to homebuyers and refinancers alike.

The last time mortgage rates were above 6 percent was Nov. 2008. At that time, the average rate was 6.33 percent, meaning a $200,000 loan would have carried a monthly payment of $1,241.86. With the average rate now 4.74 percent, the monthly payment for the same size loan would be $1,042.09, a savings of $199 per month for a homeowner refinancing now.

SURVEY RESULTS

30-year fixed: 4.74% - down from 4.75% last week (avg. points: 0.39)

15-year fixed: 4.22% - up from 4.20% last week (avg. points: 0.36)

5/1 ARM: 4.06% - down from 4.07% last week (avg. points: 0.30)