Thirty-seven states added construction jobs between July 2014 and July 2015 before the market cooled down in the last two months, according to the Associated General Contractors of America.

Using U.S. Labor Department data, the AGC said 27 states and Washington, D.C., added jobs in June and July this year, as economic uncertainty causes some projects to be delayed or canceled.

"Construction continues to grow overall but fewer states are participating in the expansion than was true a year ago," said Ken Simonson, the association's chief economist. "The uneven growth reflects the cross-cutting trends in the overall economy, as tight government budgets, plunging commodity prices and weak overseas demand lead to project cancellations in some states even while activity accelerates elsewhere."

States adding a high number of jobs include California, Florida, Washington and Texas.