The number of housing markets on the National Association of Home Builders/First American improving markets index surpassed 100 in October.

Eleven markets joined the list, while seven dropped off, taking the total to 103 from 99 in September. It’s the largest number of metros on the index since it was created a year ago. Thirty-three states and the District of Columbia are represented.

The markets added to the list in October include Santa Cruz, Calif., Pocatello, Idaho, Abilene, Texas, and Savanna, Ga.

Those that fell off are Jacksonville, Fla., Lakeland, Fla., Bloomington, Ind., Lawton, Okla., Bend, Ore., Texarkana, Texas, and Charlottesville, Va.

"The fact that most markets are maintaining their spots on the improving list from month to month is an important indication that the recovery trend is solidifying," NAHB Chief Economist David Crowe said. "At the same time, overly tight credit conditions are certainly constraining consumers' ability to purchase homes as well as builders' ability to construct them."

The NAHB/First American IMI 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. An area must see improvement in all three measures for at least six months following those measures' respective troughs before being included on the list.