Mortgage rates dropped below the 5 percent mark, with the benchmark conforming 30-year fixed mortgage rate now 4.96 percent, according to Bankrate.com's weekly national survey. The average 30-year fixed mortgage has an average of 0.44 discount and origination points.

The average 15-year fixed mortgage retreated to 4.16 percent, and the larger jumbo 30-year fixed rate hit the low point of the year at 5.44 percent. Adjustable rate mortgages got in on the act, with the average 5-year ARM sinking to 3.7 percent and the 7-year ARM sliding to 4.03 percent.

Mortgage rates moved below the 5 percent threshold despite a negative credit outlook on U.S. government debt. The movement was counterintuitive but came as a result of nervousness about the economic recovery, either from pressure to dial back government stimulus in the face of mounting deficits or from the economic risk posed by rising oil prices. But the movement in mortgage rates continues to be tame, with rates remaining within a one-third percentage point band since mid-December. Mortgage rates are closely related to yields on long-term government bonds.

The last time mortgage rates were above 6 percent was Nov. 2008. At the time, the average 30-year fixed 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 4.96 percent, the monthly payment for the same size loan would be $1,068.76, a difference of $173 per month for anyone refinancing now.

SURVEY RESULTS

30-year fixed: 4.96% - down from 5.07% last week (avg. points: 0.44)

15-year fixed: 4.16% - down from 4.28% last week (avg. points: 0.38)

5/1 ARM: 3.70% - down from 3.83% last week (avg. points: 0.40)