More bad news on the economy sent mortgage rates down for the third straight week to a 30-month low.

The average rate on a 30-year, fixed-rate mortgage fell 18 basis points to 5.69% during the week ended Thursday, according to a survey by Freddie Mac ( FRE).

A basis point is a hundredth of a percentage point.

Over the past three weeks, 30-year mortgage rates have fallen by a cumulative 45 basis points. Freddie says that's the steepest three-week decline since September 2003.

At this time last year, rates on 30-year fixed-rate mortgages averaged 6.23%.

The news wasn't all good: Those looking to purchase a home or refinance an existing mortgage can now expect to pay origination fees and discount points of 0.5% of the total loan amount, on average. That's up slightly from 0.4% last week.

And unlike the last time mortgages hit this level, banks are no longer in a hurry to throw their money at all comers. Skittish about having to keep risky loans on their books, banks are reluctant to refinance people with subprime or jumbo loans.

The falling mortgage rates came on news of a slump in retail sales, which fell 0.4% in December from November.

"The declines aggravated concerns about the well being of the economy and exerted downward pressure on mortgage rates," Frank Nothaft, Freddie Mac vice president and chief economist, said in a release. "Particularly weak were sales of building materials, garden equipment and supply stores, which fell by 2.9% from the previous month."

Other mortgage rates were also lower on the week.

Rates on 15-year fixed-rate mortgages fell 22 basis points to 5.21%, with average points of 0.4%; rates on five-year Treasury-indexed hybrid adjustable-rate mortgages, or ARMs, fell 23 basis points to 5.40%, with average points of 0.6%; and rates on one-year Treasury-indexed ARMs fell 11 basis points to 5.26%, with average points of 0.6%.

Freddie Mac surveys lenders about rates on conventional mortgages of less than $417,000 to borrowers with good credit.

The survey doesn't reflect rates on jumbo loans of over $417,000 or loans to borrowers with weak credit.

Freddie Mac's numbers are averages. You can search for the best rates offered by lenders in your area on . Just make sure you understand whether the lender is discounting the rate it quotes you by charging a "point," or fee, based on the size of the loan.

Mortgage Rates in Selected Cities
City Term Rate
Boston 30-year fixed 5.75%
New York 30-year fixed 5.375%
Denver 30-year fixed 5.75%
Chicago 30-year fixed 5.625%
Milwaukee 30-year fixed 5.75%
--no origination fee / 20% down payment / excludes Internet banks / excludes credit unions / loans under $417,000

For more rates, see