WASHINGTON (AP) — 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.

Rates on five-year adjustable mortgages, though, ticked up to 2.81 percent from 2.80 percent.

To calculate average mortgage rates, Freddie Mac surveys lenders across the country at the beginning of each week. The average doesn't include extra fees, known as points, which most borrowers must pay to get the lowest rates. One point equals 1 percent of the loan amount.

The average fee for a 30-year mortgage fell to 0.5 point this week from 0.6 point last week. The fee for a 15-year loan was unchanged at 0.5 point. The on five-year adjustable rate loans slipped to 0.4 point from 0.5 last week.

Low mortgage rates have combined with an improved job market to bolster demand from possible buyers. But drastically fewer sellers are coming into the market. The number of properties for sale is dwindling despite buyer enthusiasm. That is pushing prices higher but hobbling home sales.