Home prices remained unchanged in January from a downwardly adjusted December level, but fell 0.8% from a year earlier, according to the Federal Housing Finance Agency's index.

The seasonally adjusted purchase-only index, calculated using mortgages sold to or guaranteed by Fannie Mae and Freddie Mac, is roughly at February 2004 levels and 19.2% below its April 2007 peak. The actual value is 182.9.

The FHFA also adjusted its 0.7% monthly increase estimate for December down to a more modest 0.1%.

The region made up of North Dakota, South Dakota, Minnesota, Nebraska, Iowa, Kansas and Missouri saw the largest increase, up 4.7% from last month. Other regions saw either marginal growth or declines, with the biggest drop of 1.7% in Oklahoma, Arkansas, Texas and Louisiana.

Only prices in the region including the Dakotas rose from January 2011, up 5.2%. New England prices fell 3.5% from a year earlier.