NEW YORK  Mortgage rates fell for the second straight week to the lowest point in five decades. But many people either dont qualify for new mortgages or have already taken advantage of the low rates this year.

As a result, the housing market and the broader economy may not benefit much from the lower rates.

The average rate on a 30-year fixed mortgage dropped to 4.57 percent last week, mortgage company Freddie Mac reported Thursday. Thats down from the previous record low of 4.58 percent set the previous week.

Its the lowest since Freddie Mac began tracking rates in 1971. The last time rates were lower was in the 1950s, when most long-term home loans lasted just 20 or 25 years.

Low rates have yet to fuel home sales.

The housing market has slowed since federal tax credits for homebuyers expired at the end of April. And the latest decline in mortgage rates is unlikely to boost the market.

Mortgage rates have hovered near record lows for some time, so most people who can afford to buy homes or qualify to refinance their loans have already done so in the past 18 months.

Doing so again wouldnt be worth the cost for most.