Mortgage applications to lenders fell 2.3% for the week ending Dec. 10, the third straight week of declines according to the Mortgage Bankers Association weekly survey. The MBA refinance index fell 0.7% as well, the fifth straight week of declines, but the refinancing share of the mortgage activity grew to 76.7% of total applications, up from roughly 75% the week before. Purchase applications fell 5% after climbing for three consecutive weeks. Michael Fratantoni, MBA's vice president of research and economics, said with Treasury rates increasing after the Federal Reserve initiated QE2, mortgage rates reached their highest level in more than six months last week, pushing refinancing activity down. "Not surprisingly, with rates up more than half a percentage point over the past month, refinance activity has declined sharply. Home purchase applications dropped this week following three weeks of increases, but remain near levels last seen in early May," Frantantoni said. The MBA also monitors mortgage rates. For that week, the average interest rate on a 30-year fixed-rate mortgage increased to 4.84%, up from 4.66% the previous week. It's the highest level seen for 30-year FRM since May 2010. Rates on the 15-year FRM increased to 4.21% from 3.98%. Write to Jon Prior.