WASHINGTON – Union membership plummeted last year to the lowest level since the 1930s as cash-strapped state and local governments shed workers and unions had difficulty organizing new members in the private sector despite signs of an improving economy.

Government figures released Wednesday showed union membership declined from 11.8 percent to 11.3 percent of the workforce, another blow to a labor movement already stretched thin by battles in Wisconsin, Indiana, Michigan and other states to curb bargaining rights and weaken union clout.

Overall membership fell by about 400,000 workers to 14.4 million, according to the Bureau of Labor Statistics. More than half the loss, about 234,000, came from government workers, including teachers, firefighters and public administrators.