WASHINGTON (AP) — Mortgage applications continued to rise last week, as low interest rates allowed borrowers to refinance their home loans at the lowest rates in decades.

The Mortgage Bankers Association said Wednesday its seasonally adjusted weekly application index climbed 4.7 percent for the week ended April 3. The index came in at 1,250.6, up from 1194.4 a week earlier. It was the highest level of applications since the week ending Jan. 9, when the index hit 1324.8.

About 78 percent of applications came from borrowers seeking to refinance home loans at lower rates, rather than purchase homes.

The trade group's application index remains below its peak of 1,856.7, reached in May 2003 at the height of the housing boom.

The survey covers about half of all new residential mortgage loans made each week, covering mortgage bankers, commercial banks and thrifts.

An index value of 100 is equal to the application volume on March 16, 1990, the first week the MBA tracked application volume.

Seeking to prop up the ailing U.S. housing market, the Federal Reserve has committed to buy up to $1.2 trillion in mortgage-backed securities and $300 billion in long-term government debt. That move has pushed down mortgage rates to record lows.

The average rate for traditional, 30-year fixed-rate mortgages increased to 4.73 percent from 4.61 percent a week earlier, according to the MBA report.

The average rate for 15-year fixed-rate mortgages rose to 4.49 percent from 4.45 percent a week earlier, while the average rate for one-year adjustable-rate mortgages increased to 6.23 percent from 6.20 percent.

Copyright 2009 The Associated Press.