Construction's total workforce was flat in June, but the industry's unemployment rate declined from May's level and showed strong year-over-year improvement, the Bureau of Labor Statistics said.

The latest BLS report on the nation's employment picture, released on July 2, showed that construction's June jobless rate edged down to 6.3% from the previous month's 6.7%.

June's figure also was markedly better than 8.2% a year previously, marking the 57th straight month of year-over-year jobless-rate decreases for the industry. The BLS unemployment rates are not adjusted for seasonal variations.

BLS also reported that the industry's workforce totaled 6,380,000 in June, the same as in May.

Ken Simonson, Associated General Contractors of America chief economist, noted that the June and May numbers were the highest since March 2009.

He traced June's lack of jobs growth to the problems construction contractors have had in finding experienced workers. He said, "This scarcity shows up in record workweeks for craft workers and flattening of employment totals despite higher construction spending."

Anirban Basu, Associated Builders and Contractors chief economist, said, "At first glance, this jobs report looks like a clunker," but he agreed that firms' search for workers may help explain the leveling off in construction employment.

"Moreover," Basu said, "there are skills mismatches between the construction labor that is available and the demands of expanding construction firms operating in infrastructure, commercial and other segments."

He added, "The implication is that construction wage growth could be significant going forward and that [June's] weak construction jobs report does not necessarily signal falling demand for human capital."

The jobs results for various construction sectors were uneven—and  puzzling.

The non-residential building segment was the strongest, gaining 4,500 jobs, but non-residential specialty-trade contractors lost 5,600.

On the other hand, residential building was the weakest category, shedding 6,100 positions, but residential specialty-trade firms' payrolls expanded by 3,700.

One positive note was the heavy and civil engineering sector's pickup of 3,800 jobs during June, despite uncertainty over federal highway and transit funding.

AGC's Simonson observed that, compared with June 2014 jobs levels, the residential construction categories as a group were up 5.5% and non-residential segments increased 3.5%.

Architectural and engineering services—which BLS lists separately from construction—saw its workforce expand by 4,400.

BLS also reported that the U.S. economy overall added 223,000 jobs in June, pushing the national unemployment rate down to 5.3% from May's 5.5%.