Mortgage refinancings rose 17.1% last week and now account for 81.4% of total mortgage applications, according to the Mortgage Bankers Association. The association said in its weekly survey that the refinance index for the week ended Aug. 13 reached its highest level since May 2009, and the refinancing share of overall mortgage applications last week was at the highest rate since January 2009. Mortgage rates hit all-time lows earlier this year and are still at levels not seen for decades, with many lenders currently offering 15-year fixed-rate loans lower than 4% and 30-year fixed in the 4.25%-4.5% range. MBA's seasonally adjusted market composite index, which measures weekly gross mortgage loan applications, rose 13% from the prior week. The seasonally adjusted purchase index declined 3.4% from a week earlier and is 38.6% lower than the same week a year ago, according to MBA. In a separate survey, Mortgage Maxx said household application activity for the week rose 5.9% from the previous week. The firm's Mortgage Application Index — or MAX — measures household activity in the application process by adjusting total application volume to count multiple submissions from a single household as one participant. MAX publisher Paul Descloux said the index "shows strength as the 10-year treasury again reaches crisis mode yields. Not only have long dated mortgages fallen to 4.5%, but some old favorites like 5/1 interest only are down in the low 3’s." Write to Jason Philyaw.