Mortgage applications in the U.S. climbed last week as record-low borrowing costs spurred home purchases and refinancing.

The Mortgage Bankers Association’s index rose 6.2 percent in the period ended Dec. 7 from the prior week, the Washington- based group said today. The group’s purchase measure gained 0.7 percent to the highest level in a year, and its refinancing gauge advanced 8 percent.

The average rate on a 30-year fixed loan dropped to 3.47 percent, the lowest in records dating back to 1990, from 3.52 percent the prior week. Borrowing costs on a 15-year fixed mortgage fell to 2.85 percent from 2.86 percent.