Construction employment increased in 39 states between June 2015 and June 2016, although half of the states shed construction jobs between May and June, according to an analysis of U.S. Labor Department data released by the Associated General Contractors of America.

“Construction demand is growing strongly in all regions and among many types of owners,” said Ken Simonson, the association’s chief economist. “But contractors appear to be struggling to fill jobs in the short run.”

Simonson said recent data shows a spike in job openings at construction firms, but a huge decline in the number of experienced construction workers who are available for hire. Association officials added that 70 percent of firms reported earlier this year that they’re having problems finding qualified workers.

“Shortages of qualified workers appear to be causing construction employment to stall in many parts of the country, and that lack threatens to affect broader economic conditions,” said Stephen Sandherr, the association’s CEO. “Public officials need to act without delay to step up investments in the types of skills-based education programs that enable students to succeed in school and land high-paying jobs in fields like construction.”

According to the analysis, Hawaii had the highest percentage of new construction jobs during the last year, with 15.9 percent or 6,700 jobs added, followed by Iowa with 15.8 percent or 12,200 jobs added. Construction employment declined in 11 states, including the District of Columbia, with North Dakota losing the largest number of construction jobs for the year at a loss of 12.4 percent or 4,300 jobs.

View the state employment data by rank and state, or the state employment map via AGC of America’s website.