U.S. mortgage applications to buy a home decreased to their lowest levels in nearly six months last week even as most home borrowing costs fell, data from the Mortgage Bankers Association released this week showed.

The Washington-based group’s seasonally adjusted index on borrowers’ requests for home purchases to lenders, which is seen as a proxy on future housing activity, fell 3.3 percent to 225.5 in the week ended Aug. 10. This matched a reading set in the week of Feb. 16.

The average contract interest rate for 30-year fixed-rate mortgages with conforming loan balances ($453,100 or less) decreased to 4.81 percent from 4.84 percent.

The average contract interest rate for 15-year fixed-rate mortgages increased to 4.27 percent from 4.26 percent.