WASHINGTON (AP) — Average U.S. rates on fixed mortgages rose for the second straight week, staying slightly above historic lows.

Mortgage buyer Freddie Mac says the rate on the 30-year loan increased to 3.59 percent, up from 3.55 percent last week. Two weeks ago, the rate fell to 3.49 percent, the lowest since long-term mortgages began in the 1950s.

The average rate on the 15-year fixed mortgage, a popular refinancing option, rose to 2.84 percent. That's up from 2.83 percent last week and a record low of 2.80 percent the previous week.

Cheap mortgages have helped drive a modest housing recovery this year. Home sales are higher than last year, although they are still below healthy levels.

U.S. home prices are also rising. Prices for all homes, including distressed properties, jumped 2.5 percent in June from the same month in 2011, according to a report issued Tuesday by data analytics firm CoreLogic.

Builders have grown more confident after seeing increased demand for homes. In June, they increased their spending for a third straight month.

Low mortgage rates could also provide some help to the economy if more people refinance. When people refinance at lower rates, they pay less interest on their loans and have more money to spend. Many homeowners use the savings on renovations, furniture, appliances and other improvements, which help drive growth.

Still, the pace of home sales remains well below healthy levels. Many people are still having difficulty qualifying for home loans or can't afford larger down payments required by banks.

Mortgage rates are low because they tend to track the yield on the 10-year Treasury note. A weaker U.S. economy and uncertainty about how Europe will resolve its debt crisis have led investors to buy more Treasury securities, which are considered safe investments. As demand for Treasurys increase, the yield falls.

To calculate average rates, Freddie Mac surveys lenders across the country on Monday through Wednesday of each week.

The average does not 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 30-year loans was 0.6 point, down from 0.7 point last week. The fee for 15-year loans also was 0.6 point, unchanged from the previous week.

The average rate on one-year adjustable rate mortgages fell to 2.65 percent from 2.70 percent. The fee for one-year adjustable rate loans was unchanged at 0.4 point.

The average rate on five-year adjustable rate mortgages rose to 2.77 percent from 2.75 percent last week. The fee remained at 0.6.