Construction employment expanded in two-thirds of all states in December and in half the nation last year as the industry showed signs of emerging from a six-year slump, according to an analysis by the Associated General Contractors of America of Labor Department data.

Association officials noted that contractors responding to a recent survey expect to add more workers in 2013.

“These results show that contractors are finding work in more parts of the country than they have for many months,” said Ken Simonson, the association’s chief economist. “Further gains appear likely but could be derailed if lawmakers do not keep debt markets operating normally.”

For 2012 as a whole, 24 states and the District of Columbia added construction jobs, 24 shed workers and two — Vermont and West Virginia — had no change. Nebraska jumped to the top ranking for percentage of new construction jobs (10.1%, 4,100 jobs); followed by D.C. (7.3%, 900 jobs); Texas (6.6%, 36,800 jobs); Hawaii (6.5%, 1,800 jobs) and Washington (6.5%, 9,000 jobs).

Texas added the most new construction jobs over the past 12 months, followed by California (24,500 jobs, 4.4%), Washington and Arizona.

Among states losing construction jobs during the past year, Rhode Island lost the highest percentage (-6.7%, -1,100 jobs), followed by Delaware (-5.8%, -1,100 jobs); Mississippi (-5.6%, -2,700 jobs) and Arkansas (-5.6%, -2,600 jobs).

Illinois lost the most jobs (-8,600 jobs, -4.5%); followed by Pennsylvania (-7,700 jobs, -3.4%) and Florida (-16,800 jobs, -2.1%).

Simonson noted that 33 states and D.C. added construction jobs between November and December, while employment slipped in 16 states and held steady in Utah. Wisconsin had the largest percentage increase (5.8%, 4,900 jobs); followed by D.C. (3.9%, 500 jobs) and New Jersey (3.6%, 4,300 jobs).

Utah had no change in construction employment over the month, while 16 states lost jobs, with Rhode Island having the steepest percentage drop (-5.6%, -900 jobs); followed by Montana (-4.1%, 1,000 jobs) and Minnesota (-3.6%, 3,500 jobs). Texas lost the largest number of jobs for the month (-4,100 jobs, -0.7%); followed by Florida (-3.500 jobs, -1.1%) and Minnesota.

“Construction spending has been rising for two full years but contractors have been cautious about adding workers until they knew the upturn would last,” Simonson explained. “In 2013, both residential and private nonresidential construction should rise enough to offset a further slowdown in public work, and contractors will be looking for more workers.”

Association officials said the monthly construction employment gains were consistent with results of its recently released 2013 Construction Hiring and Business Outlook, where 31% of firms reported plans to add new workers this year compared to only 9% that plan to make layoffs, a net positive reading of 22%. Officials cautioned that construction firms still face significant headwinds, noting that most firms expect public construction activity to continue to decline and remain cautious about plans to acquire new equipment.

“There is a growing sense of optimism within the construction community that the worst is over,” said Stephen E. Sandherr, the association’s chief executive officer. “At the same time, however, just because the worst is over doesn’t guarantee that conditions are going to get significantly better anytime soon, especially if Washington can’t find a way to address out-of-control entitlement spending that is making it increasingly difficult to invest in aging infrastructure and other important construction programs.”