NEW YORK, Oct 29 - Applications for mortgages to buy U.S. homes fell 5.7 percent last week, a trade group said on Wednesday, suggesting that current mortgage rates may be starting to dent record-high home sales. "The pace of home sales that we've seen for the last few months is not sustainable for much longer," said Celia Chen, housing economist at Economy.com, on Tuesday. The job market is showing early signs of stabilizing, but is still weak, and mortgage rates are rising, Chen said. The Mortgage Bankers Association of America said on Wednesday that its index of applications for mortgages to buy homes, on a seasonally adjusted basis, fell 5.7 percent to 363.9. That decline helped drag overall mortgage applications down by 0.5 percent, bringing the MBA's market index down to 649.6. To be sure, applications for mortgages to buy homes were still relatively strong last week, at just 6.85 percent below the average for the year. But economists generally expect purchase activity to moderate after what is likely to be a record setting year. Existing home sales reached a record in September, rising 3.6 percent to a record seasonally adjusted 6.69 million rate, a report on Monday said. New home sales were off 0.2 percent in September to a seasonally adjusted 1.145 million rate, but were still near record highs. The housing and mortgage sector, which has fueled about two-thirds of economic growth since 2000, could stop driving growth by the middle of next year, Chen said. The 30-year mortgage rate drifted 0.14 percentage points lower last week to 5.83 percent, which is within the range it has hovered in since late July, but over 3/4 of a percentage point above the record lows reached in June. The slight declines in rates last week spurred applications to refinance mortgages to rise 4.9 percent, bringing the Mortgage Bankers Association's refinancing index to 2,311.8. Even after last week's rise, the refinancing index was more than 75 percent below the record set in late May.//