Falling interest rates pushed mortgage applications up 12.8 percent last week on a seasonally adjusted basis, according to the Mortgage Bankers Association weekly survey.

On an unadjusted basis, the index rose 24.6 percent compared to the previous week and was up 14 percent compared to the same week a year ago.

Most of the applications were for refinances, with that index rising 17.4 percent, while the purchase index rose 5.6 percent.

The percentage of homes being purchased with government-guaranteed instruments was at 45.7 percent, the highest it has been over the life of the bankers’ survey.

Average mortgage rates fell below 5 percent:

• 30-year fixed-rate mortgages decreased to 4.97 percent from 5.08 percent.
• 15-year fixed-rate mortgages remained unchanged at 4.41 percent.
• 1-year ARMs decreased to 6.52 percent from 6.61 percent.

Source: Mortgage Bankers Association