Mortgage rates fell significantly after three weeks of rising sharply.

The average 30-year fixed-rate dropped 19 basis points, to 5.76 percent. A basis point is one-hundredth of a percentage point.

This week's average 15-year fixed-rate -- a popular option for refinancing – slid 18 basis points, to 5.19 percent.

The average jumbo 30-year fixed ticked up 1 basis point to 6.97 percent.

Adjustable-rate mortgages also fell this week. The one-year adjustable-rate mortgage declined 6 basis points to 5.1 percent. The popular 5/1 ARM dropped 12 basis points, to 5.37 percent.

Mortgage application activity fell sharply for the fourth straight week, according to the Mortgage Bankers Association. Overall activity was down 15.8 percent when compared to one week earlier.

Refinancing activity tumbled 23.3 percent. Applications for new purchase fell a more modest 3.5 percent.

In other housing news:

• Housing starts jumped 17.2 percent in May compared with one month earlier, according to the Census Bureau. However, May housing starts (annual rate of 532,000) remain 45.2 percent lower than housing starts in May 2008 (annual rate of 971,000).

• Foreclosure activity fell 6 percent nationwide during May compared with the record high recorded in April, according to online foreclosure marketer RealtyTrac. However, activity was still 18 percent higher than in May 2008, and the overall number of foreclosures (321,480) exceeded 300,000 for the third straight month.

To find and compare mortgage rates in your area, visit Bankrate's interactive search tool.

-- Chris Kissell