In January, the number of homes still hidden in the shadows fell to 2.2 million, a 28 percent decrease from the January 2010 peak when an estimated three million housing units were in shadow inventory, data fromCoreLogic.

The data provider’s calculation is based on the number of properties that are seriously delinquent, in foreclosure, or bank-owned, but not yet listed on multiple listing services.

The 2.2 million units represent a supply of nine months and a year-over-year decline of 18 percent from January 2012, CoreLogic reported.

“The shadow inventory continued to drop at double the rate in January from prior-year levels. At this point in the recovery, we are seeing healthy reductions across much of the nation,” said Anand Nallathambi, president and CEOof CoreLogic.

Seriously delinquent loans were the main drivers of shadow inventory, accounting for one million (4.1 months’ supply) of the distressed properties yet to be released, according to CoreLogic. Foreclosures in shadow inventory totaled 798,000 (3.2 months’ supply), and REOs in the shadows numbered 342,000 (1.4 months’ supply).

Shadow inventory also represents 85 percent of the 2.6 million properties that are seriously delinquent, in foreclosure, or bank-owned.

The states that saw the steepest drop in serious delinquencies over a one-year period ending in January were Arizona (-40 percent), California (-33 percent), Colorado (-27 percent), Michigan (-25 percent) and Wyoming (-23 percent).

“The shadow inventory is declining steadily as properties are moving through the distressed pipeline,” said Dr. Mark Fleming, chief economist for CoreLogic. “States like Arizona, California and Colorado are experiencing significant declines year over year in the stock of serious delinquencies, a positive sign for further improvement in the shadow inventory.”

Florida, on the other hand, accounts for 16 percent of the nation’s distressed properties. As of January, five states—Florida, California, New York, Illinois, and New Jersey-accounted for 44 percent of all distressed properties in the country.

“As we move forward in 2013, we need to see more progress in Florida, New York, California, Illinois and New Jersey which now account for almost half of the country’s remaining shadow inventory,” Nallathambi added.

by Esther Cho