The Improving Markets Index, an indicator of the housing industry's strength in major metropolitan areas across the U.S., gave up eight net markets from June to July, falling from 263 to 255. Despite the decline, about 70 percent of all 361 metropolitan areas have qualified for the index for six consecutive months, a positive sign for housing market growth.

A total of 255 metropolitan areas qualified for the National Association of Home Builders/First American Improving Markets Index (IMI) in July. The total is down from the 263 metros that made the list in June, but is more than triple the number of markets on the index in July 2012.

Six new markets were added to the list and 14 were dropped from it in July, spanning 49 states and the District of Columbia. Newcomers include Cumberland, Md.; Saginaw, Mich.; Farmington and Las Cruces, N.M.; Kingston, N.Y.; and Olympia, Wash.

"This is the sixth straight month in which at least 70 percent of all U.S. metros have qualified for the Improving Markets Index," NAHB chairman Rick Judson said. "The relative stability of the IMI is representative of the broad recovery underway, which is much more extensive than what we were looking at one year ago."

The IMI tracks three sets of independent monthly data – employment growth from the Bureau of Labor Statistics, house price appreciation from Freddie Mac, and single-family housing permit growth from the U.S. Census Bureau – to get a reading on the top metropolitan areas. A market must improve in all three measures for at least six consecutive months before reaching the index.

"Based on recent trends in home prices, housing permits, and employment, the outlook for a continued housing expansion remains very positive for the remainder of 2013," NAHB chief economist David Crowe said.

A complete list of all 255 metros currently on the IMI, and separate breakouts of metros newly added to or dropped from the list in July, is available at nahb.org/imi.