The construction industry added jobs in 40 states between May 2014 and May of this year, the Associated General Contractors of America says.

Twenty-eight states also saw job gains in April and May this year, the association added, citing Labor Department figures.

However, the AGC said, the states adding jobs are inconsistent as many markets remain in flux.

Construction has outpaced the overall economy in adding workers nationally but the mix of states with construction job gains keeps changing," said Ken Simonson, the association's chief economist. "The top 10 states for job gains from April to May had previously lagged in adding construction workers, while energy-producing and other states that had record construction employment a few months ago have slipped."

The top state for added construction jobs in the past year was California, with 46,600 jobs added. Other top states include Florida, Texas, Washington and North Carolina, the association said.