(Reuters) - Labor union membership as a percentage of the U.S. work force stabilized at 11.3 percent in 2013 after several years of declines, government figures showed on Friday.
In an era of diminished power for unions in the economy, the Labor Department reported that there were 14.5 million union members last year, about level with 2012.
By comparison, in 1983, the first year for which the department published comparable data, union membership was 20.1 percent, with 17.7 million U.S. union workers.
Union membership in the private sector grew slightly in 2013 to 6.7 percent from 6.6 percent. This was offset by a drop in the percentage of public-sector employees belonging to unions to 35.3 percent in 2013 from 35.9 percent in 2012, data showed.
A major political clash over public-sector unions unfolded in Wisconsin, which imposed new restrictions on public-sector unions in 2011. The limits were blocked by the courts for part of 2012, but an impact was apparent.
Union representation among Wisconsin's public-sector employees, including union members and workers who do not pay union dues but still enjoy union contract pay and benefits, dropped to 37.6 percent in 2013 from 53.4 percent in 2011.
The latest U.S. data suggest, "the erosion of public sector union coverage reflects the new anti-collective bargaining policies implemented in several states," said Lawrence Mishel, president of the liberal-leaning Economic Policy Institute.
In the private sector, utilities had the highest union membership at 25.6 percent, followed by transportation and warehousing at 19.6 percent.
In the public sector, local government employees, including teachers, police officers and firefighters, reported the highest union membership at 40.8 percent, said the department.
Workers in education, training, library and protective service reported higher union membership than other fields, about 35.3 percent each, according to government data.
The states that reported the most growth across all sectors and fields included Alabama, Nebraska, Tennessee, Kentucky, New York, Illinois and Wisconsin.
States with steep declines in membership included Louisiana, Oregon, Utah, Wyoming, New Hampshire, Montana and Texas.
The Center for Union Facts, which criticizes unions, attributed the slight uptick in private-sector representation to the labor movement's response to the defeat of proposed legislation that would have eased the unionization process.
"While this uptick is by no means a tectonic shift in the long-term trend of waning union membership, it certainly is something employers should pay attention to going forward," said J. Justin Wilson, the center's managing director.
Black workers had the highest union membership rate in 2013, at 13.6 percent, followed by whites, at 11 percent, and Asians, at 9.4 percent, according to the Labor Department data.
Male workers reported a union membership rate of 11.9 percent and women a rate of 10.5 percent in 2013, the department said.
Young workers were less likely to belong to a union than older people. Just 4.2 percent of workers 16 to 24 years old were union members, compared with 14 percent of those aged 45 to 54.
Additional reporting by Bernie Woodall in Detroit; Editing by Kevin Drawbaugh and Andre Grenon