Average rate on 30-year mortgage slips to 3.42%

Long-term U.S. mortgage rates slipped this week to the lowest level since mid-July.

Mortgage giant Freddie Mac says the average for a 30-year fixed-rate mortgage dropped to 3.42 percent, down from 3.48 percent last week. The benchmark rate is down from 3.85 percent a year ago and is close to its all-time low of 3.31 percent in November 2012. The 15-year fixed-rate mortgage, popular with homeowners who are refinancing, slipped to 2.72 percent from 2.76 percent.

The rates tumbled after the Federal Reserve decided against raising short-term rates at its meeting last week.

To calculate average mortgage rates, Freddie Mac surveys lenders across the country at the beginning of each week.