A sustained uptick in home prices in more metros caused the number of improving housing markets across the nation to rise to 99 in September from 80 the previous month, according to the National Association of Home Builders and First American (FAF).

The total includes cities from 33 states as well as the District of Columbia.

"The number of improving housing markets grew by 19 in September as 68 metros retained their spots, 31 new metros were added and just 12 dropped off the list," noted NAHB Chairman Barry Rutenberg.

In addition to home prices, the NAHB/First American index identifies areas that are showing improvement from their respective troughs in housing permits, employment and house prices for at least six consecutive months.

Markets added to the list in September include Tucson, Ariz., Jacksonville, Fla., Springfield, Ill., Greenville, N.C. and Bend, Ore.

"This solid growth is an encouraging sign that housing continues on a slow but steady recovery path that is gradually advancing from one local market to the next,” Rutenberg said.

The index measures employment growth from the Bureau of Labor Statistics, house price appreciation from Freddie Mac and single-family housing permit growth from the Census Bureau.

"Combined with recent positive reports on builder confidence, housing starts and new-home sales, the September IMI adds to the growing consensus that housing is finally moving in the right direction," Kurt Pfotenhauer, vice chairman at First American, said.