'Ancient' may be the best word to describe New Jersey's housing inventory.

Flickr User Lee Cannon

Nationwide, 71 percent of single-family homes were built before 1990, according to RealtyTrac. The percentage is ten points higher in New Jersey. In fact, 19 percent of the Garden State's homes were constructed before 1940.

Daren Blomquist, Vice President of RealtyTrac, said older homes can present both a challenge and an opportunity for a state's housing market. An aging stock means more money spent on repairs and maintenance by owners and sellers, but on the buyer side, homes built before 1990 can be much lower in price.

"Specifically in New Jersey, we're showing the average price of a home built before 1990 is about $307,000, whereas the average price of a home built 1990 to current is over $400,000," said Blomquist.

Homes older than 1990 made up more than 80 percent of year-to-date 2013 sales in New Jersey and 13 other states. In contrast, older homes made up less than 40 percent of 2013 sales in Utah and Nevada.

RealtyTrac pointed to the Federal Housing Administration's 203(k) program as the "government's answer" to the aging housing supply.

"Owner-occupant buyers can take advantage of the 203(k) program to finance the purchase, rehab, and upgrade of an older home," explained RealtyTrac. "Homeowners can also advantage of the program to roll rehab costs into a refinance."