Construction firms added jobs in 40 states and the District of Columbia between May 2014 and May 2015, according to an analysis of US Department of Labor data released today by the Associated General Contractors of America. Association officials said the mix of states adding and losing construction jobs continues to vary amid fluctuations in demand.

Idaho posted the largest year-over-year percentage increase in construction employment at 11.8%. However, California led in terms of total number of jobs added with 46,600 jobs added year over year.

“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.”

Ten states shed construction jobs during the past 12 months. West Virginia lost the highest percentage of jobs at 12.3%, while Ohio lost the highest total number of jobs at 4,300 jobs.