Union membership in 2012 declined to 11.3 percent of U.S. wage and salary workers last year, down from 11.8 percent in 2011.

The number of wage and salary workers belonging to unions, 14.4 million, also declined over the year.

In addition, the reported noted that in 2012, among full-time wage and salary workers, union members had median weekly earnings of $943, while those who were not union members had median weekly earnings of $742.

According to a U.S. Bureau of Labor Statistics’ annual report, only 6.6 percent of the private-sector workforce belonged to a union last year, compared to 35.9 percent of employees in the public sector.

The report said 7.3 million union members worked in the public sector and 7 million worked in the private sector.

The 2012 report continued to show the decline in union membership, which has been occurring since the 1950s and stepped up pace in the 1980s. Union losses heightened since the recent recession.

In 1983, the first year for which comparable union data are available, the union membership rate was 20.1 percent, and there were 17.7 million union workers.

Workers in education, training, and library occupations and in protective service occupations had the highest unionization rates last year, at 35.4 and 34.8 percent, respectively, the bureau reported.

In the public sector, local government workers — including teachers, fire fighters and police — were most likely to be unionized.

In the private sector, union membership was highest in the transportation and utilities industries.

The report also noted that some workers are represented by unions under collective bargaining agreements but are not themselves union members.

In all, about 15.9 million workers were represented by such collective bargaining. Private-sector employees were about half of the 1.6 million workers who were covered by a union contract but were not members of a union.

New York continued to have the highest union membership rate at 23.2 percent, while the lowest union rate was in North Carolina, 2.9 percent.

The full report is online at bls.gov.