Construction employment continued its spotty improvement in July, as more states posted year-over-year gains but most states posted decreases from June, according to an analysis by the Associated General Contractors of America of Labor Department data.

“Today’s report shows the fragile and fragmentary nature of the industry’s recovery,” said Ken Simonson, the association’s chief economist. “Construction employment increased in 37 states during the past 12 months – the largest number with gains since early last year – but only two states have surpassed their pre-recession peaks, and barely a third of states added construction jobs between June and July.”

Both the widespread annual gains and monthly losses were consistent with national totals for July, Simonson noted. Labor Department data released earlier this month showed construction employment rose 3 percent from July 2012 to July 2013, but slipped by 0.1 percent, seasonally adjusted, in the latest month.

The largest year-over-year percentage increases in construction jobs were in Wyoming (up 16.7 percent, 3,500 jobs), followed by Mississippi (up 12.3 percent, 5,800 jobs) and Hawaii (up 11.6 percent, 3,400 jobs). The steepest declines occurred in Indiana (down 6.7 percent, down 8,300 jobs) and South Dakota (down 6.7 percent, down 1,400 jobs).

Only 18 states added construction employees between June and July, while 30 states and D.C. lost jobs. There was no change in Massachusetts or Texas.

Association officials said that after years of layoffs and slow demand, many unemployed skilled construction workers had likely either retired or switched industries. They noted that should demand for new construction expand, many firms indicate they are likely to face shortages of available skilled workers.

View the state employment data by rank, by state and by change from peak.