For the sixth straight week, fixed mortgage rates inched down, reaching new lows for 2011. The 30-year fixed-rate mortgage averaged 4.60 percent this week while the 15-year mortgage averaged 3.78 percent, Freddie Mac reports in its weekly mortgage market survey.

Meanwhile, the National Association of Home Builders reported this week that home affordability reached its highest level in 20 years, making the purchasing power for home buyers even better during this traditionally prime buying season.

Here’s a closer look at mortgage rates:

• 30-year, fixed-rate mortgage: Averaging 4.60 percent this week, it was down slightly from last week’s 4.61 percent average. Last year at this time, 30-year rates averaged 4.84 percent. The 30-year fixed rate mortgage hasn’t been under this week’s 4.60 percent average since early December 2010 when it fell to 4.46 percent.
• 15-year, fixed-rate mortgage: Averaging 3.78 percent this week, it also was down from last week’s 3.80 percent average. Last year at this time, the 15-year fixed-rate mortgage averaged 4.21 percent. It has not been under this week’s 3.78 percent average since late November 2010 when it fell to 3.77 percent.
• 5-year adjustable-rate mortgage: Averaging 3.41 percent this week, it was down from last week’s 3.48 percent average. A year ago at this time, the 5-year ARM averaged 3.97 percent.

Source: “Fixed Mortgage Rates Continue to Find New Lows,” Freddie Mac (May 26, 2011)