Fixed-mortgage rates changed little over the past four weeks, which is helping to spur new home construction, Freddie Mac said in its Primary Mortgage Market Survey.

The 30-year, fixed rate was 3.56% for the week ending Feb. 21, up from last week when it averaged 3.53%, but down from 3.95% a yea before.

The 15-year, FRM averaged 2.77% this week, the same as last week, but down from 3.19% last year.

Meanwhile, the 5-year Treasury-indexed ARM averaged 2.64%, the same as last week, but down from 2.80% a year earlier.

Additionally, the 1-year Treasury-indexed ARM averaged 2.65%, up from 2.61% last week, but down from 2.73% last year.

"Mortgage rates have been relatively stable, hovering near record lows, for the past four weeks which is helping to spur new home construction," said Frank Nothaft, vice president and chief economist for Freddie Mac.

He added, "For instance, new construction on single-family houses rose to an annualized rate of 613,000 in January, the most since July 2008. In addition, single-family building permits were up to the highest issuance level since June 2008."

Bankrate data also shows mortgage rates “showed little movement” over the past week.

The Bankrate 30-year, FRM rose to 3.80% this week, up from 3.79% a week earlier. The 15-year, FRM remained unchanged at 3.02% from last week and the 5/1 ARM increased to 2.76%, up from 2.75% from the previous week.