U.S. 30-year fixed-rate mortgage rates rose to 3.95 percent in the week ending Feb. 23 from a record low of 3.87 in the previous week, Freddie Mac said.

The average 30-year mortgage rate was 4.95 percent last year.

New data releases this week suggest the housing market is continuing to gradually improve. Loans that were seriously delinquent (90 days or more past due plus the foreclosure inventory) fell to 5.3 percent of prime mortgages at the end of 2011, representing the lowest quarterly share since the start of 2009, according to the Mortgage Bankers Association, said Frank Nothaft, chief economist and vice president of Freddie Mac, in a statement.

He noted that new residential construction starts in January beat forecasts, according to the U.S. Census Bureau, and existing home sales were at the strongest pace in January since May 2010, according to the National Association of Realtors.

The average rate for 15-year fixed-rate mortgages was 3.19 percent, up from at 3.16 percent from the previous week and down from 4.22 percent in the previous year.

Five-year Treasury-indexed adjustable-rate mortgages (ARMs) averaged 2.80 percent, down from 2.82 percent in the previous week and 3.80 percent in the previous year. One-year Treasury-indexed ARMs fell to 2.84 percent from 2.73 percent in the previous week, but down from 3.40 percent in the previous year.