The number of U.S. houses left vacant because of foreclosure was down at the start of the second quarter compared with the same period last year. But New Jersey's share of these "zombies" continues to be tops in the nation, real estate information provider RealtyTrac said Thursday.

Zombie homes are defined as houses that mortgage borrowers vacated for which the foreclosure process was never completed.

In the United States overall, just 19,187, or 4.7 percent, of residential properties in the foreclosure process were zombies as of May, according to the Irvine, Calif., company, which monitors foreclosures nationwide. New Jersey claimed 4,003 of them. Pennsylvania had 572.

In South Jersey, zombies totaled 1,268 as of May, making up 11.2 percent of homes in foreclosure in Burlington County, 9.4 percent in Camden County, and 8 percent in Gloucester County.

RealtyTrac reported that Gloucester County had the fewest foreclosures, 2,975, and the fewest zombies, 237. Burlington County had 468 zombies among its 4,185 houses in foreclosure.

Only Camden County showed a year-over-year decline, 5.5 percent, in the number of zombies. Of the region's three South Jersey counties, it had the most foreclosures, 5,967, and the most zombies, 563.

Val Nunnenkamp of Berkshire Hathaway Home Services Fox & Roach Realtors, in Marlton, agreed that Camden County's zombie numbers were down.

In Voorhees, for example, "there are still 15 or 20 of them, but last year there were 30," Nunnenkamp said.

Typically, New Jersey has a roughly three-year timeline for moving houses in foreclosure's many stages through the courts. At an average 1,103 days, it is the longest in the country. (Pennsylvania's timeline is about 554 days.) High volume has exacerbated the Garden State's situation, lawyers and experts say.

On the Pennsylvania side of the Delaware, RealtyTrac reported, zombies represented a small percentage of the total vacant homes in Bucks, Chester, Delaware, Montgomery and Philadelphia Counties and an even smaller percentage of houses in foreclosure.

Together, the five counties had only 280 homes qualifying as zombies as of May, RealtyTrac said. Philadelphia, with 131 zombies among 5,700 foreclosures, had the most, followed by:

Delaware County, with 67 zombies among 1,948 foreclosures.

Bucks County, with 26 zombies among 1,396 foreclosures.

Chester County, with 22 zombies among 358 foreclosures.

Montgomery County, with 42 zombies among 1,557 foreclosures.

Bob Acuff of Re/Max Services, in Blue Bell, who is on the board of Trend Multiple Listing Service, said sales of "distressed" homes in the Philadelphia region in the first quarter of 2016 were up 13.5 percent over the same period in 2015 and 23.8 percent over the first three months of 2014.

"We are surmising as the market has gotten stronger, the banks are releasing properties back into the market," Acuff said.

Becoming more rare, said Chris Somers of Re/Max Access, in Northern Liberties, are foreclosures as well as short sales, in which the lender agrees to accept less than is owed on a mortgage.

"There are, however, numerous vacant houses where investors try to get in contact with an owner to see if they are interested in selling," Somers said.

Martin Millner of Coldwell Banker Hearthside Real Estate, in Yardley, said there are "fewer foreclosures because of a somewhat-better economy, but also because so many of the foreclosures of three to five years ago have been sold."

RealtyTrac reported that some U.S. counties are actually running out of vacant homes of any sort (zombie or not), as demand for housing rises and supply is short.

"Lenders have been taking advantage of the strong seller's market to dispose of lingering foreclosure inventory over the past year," said Daren Blomquist, senior vice president at RealtyTrac.

Philadelphia's 12,283 vacant dwellings account for just 2.6 percent of the city's total housing inventory, RealtyTrac reported.

Lancaster County is fifth of 10 on RealtyTrac's list of those counties "running out of rooms," with 473 vacant homes, just 0.3 percent of the total.

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