NEW YORK (CNN/Money) - Rates for long-term mortgages set record lows again this week, mortgage lender Freddie Mac said Thursday.

Freddie Mac reported that the 30-year mortgage averaged 6.15 percent in the week ending Sept. 6, the lowest point since the company began recording rates in 1971, with an average of 0.6 of a point payable up front to the lender.

The rate fell from an average 6.22 percent last week and remained lower than its 6.89 percent average a year ago.

The 15-year fixed-rate mortgage averaged 5.56 percent, down from 5.64 percent last week and down from 6.44 percent last year. The 15-year rate averaged 0.6 of a point payable up front and is at its lowest point since Freddie Mac began recording the 15-year mortgage in 1991.

One-year adjustable-rate mortgages, loosely indexed to the 10-year Treasury note, averaged 4.35 percent with an average 0.6 of a point due up front, virtually unchanged from last week's 4.34 percent average. A year ago the one-year ARM averaged 5.64 percent.

"Looking for safety from the current uneasiness in domestic and foreign markets, nervous investors pumped their money into the U.S. Treasury bond market, causing yields to fall to record levels," said Frank Nothaft, Freddie Mac chief economist. "Mortgage rates followed, also dropping to yet another historic low."

Bond prices and yields move in the opposite direction.

Calculators: Your Home       Rent vs.Buy Mortgage Qualifier Refinancing calculator Rate Search Tool

Freddie Mac (FRE: down $0.62 to $62.58, Research, Estimates), or Federal Home Loan Mortgage Corp., is a publicly traded company the government established in 1970 to provide a flow of funds to mortgage lenders. It buys mortgages from banks, bundles them and then resells them as mortgage-backed securities.

Its products, and the products of other similar entities, have become increasingly popular as an alternative to government-backed bonds, particularly with international investors.