Foreclosures and short sales remained relatively frozen in December, with U.S. residential properties, including single-family homes, condominiums and townhomes, selling at an estimated annual pace of 5.16 million in December, a less than 1% increase from November and a 10% increase from a year ago, the latest RealtyTrac report found.

Annualized sales volume dropped from a year ago in 18 of the nation’s 50 largest metropolitan statistical areas and was down in five states: California, Arizona, Nevada, Rhode Island and Oregon.

In addition, the national sales price of U.S. residential properties, including both distressed and non-distressed, hit $168,391 in December, virtually unchanged from November and up 2% from December 2012.

The median price of a distressed residential property—in foreclosure or bank owned—was $108,494 in December, 38% below the median price of $174, 401 for a non-distressed residential property.

Furthermore, short sales and foreclosure-related sales — including both sales to third-party buyers at the public foreclosure auction and sales of bank-owned properties — made up 16.2% of all residential sales in 2013, up from 14.5% of all sales in 2012 and 15.2% of all sales in 2011.

"It may surprise some to see distressed sales rising in 2013 given that new foreclosure activity dropped to a seven-year low for the year," said Daren Blomquist, vice president of RealtyTrac.

"And while short sales did trend lower in the second half of the year, there are still more than 1.2 million properties in the foreclosure process or bank-owned, providing a sizable pool of inventory that the housing market is in the process of absorbing," Blomquist said. "Meanwhile, non-distressed sellers have not listed their homes for sale in droves, helping to keep the distressed share of sales at a stubbornly high level."