Union membership fell to 10.3% of the nation's workforce in 2019, down two-tenths of a percentage point from the previous year, marking the lowest level since the Labor Department began keeping track in 1983.

The Bureau of Labor Statistics reported Wednesday that the total number of workers belonging to unions had declined by about 150,000 members to 14.6 million, while the size of the overall workforce grew.

The decline follows a long, steady trend for the labor movement, which has seen traditional stronghold industries, particularly manufacturing, shrink, and that has struggled to organize new industries, such as the tech industry. A decade ago, the unionization rate was 12.3%. It stood at 20.1% when the Labor Department first began tracking the figure in 1983.

The AFL-CIO, the nation's largest labor federation, blamed the decline on the federal government. "A highly politicized National Labor Relations Board (NLRB) is abandoning its mission to uphold and protect workers' right to form unions and bargain collectively," the federation said.

The current union workforce is roughly equally split between the private sector, which accounted for 7.5 million members, and the private sector, which accounts for 7.1 million members. However, the unionization rate for private sector workers is just 6.1%, while it is at 33.6% for public sector workers.

Private sector union membership is facing pressure following a renewal in popularity in state right-to-work laws, which prohibit workers from being forced to join or otherwise financially support a union as a condition of employment. A total of 27 states have the laws, up from 22 in 2012. Public sector unions are facing similar challenges following the Supreme Court's Janus v. AFSCME decision in 2018, which effectively extends right-to-work protections to public sector workers.

"The meaningful decline in the union membership rate among local government workers (from 40.3% to 39.4%) might suggest Janus is having its intended effect," said Economic Policy Institute labor analyst Heidi Shierholz, a former Labor Department economist during the Obama administration. Other data, such as state worker unionization, shows a slight uptick to 29.4%, up from 28.6% last year, she noted, suggesting that the ruling spurred unions to put renewed effort into organizing.