The number of improved local housing markets across the United States continued to grow in February or for six months in a row, an evidence suggesting the housing recovery has substantial momentum, a leading industry report revealed Wednesday.

The number of improved markets in the month rose to 259, up from 242 in January, according to the Improving Markets Index (IMI) released by the National Association of Home Builders (NAHB).

"Just over 70 percent of the 361 metros covered by the IMI are listed as improving this month," said NAHB Chief Economist David Crowe. "That's a far cry from when we initiated this index with just 12 improving metros in September 2011."

And there was still much room for improvement, said NAHB Chairman Rick Judson, who believed that a key factor slowing this progress was the current overly stringent mortgage standards that kept qualified buyers on the sidelines.

The IMI traces housing markets throughout the country that are showing signs of improved economic health, resulting from indicators like employment growth, housing price appreciation. A metropolitan area must see improvement in all three measures for at least six consecutive months before being included on the list.