In 2015, membership in the United Autoworkers Union rose for its sixth consecutive year to 408,639. Last year, the union gained approximately 5,200 new members marking a 1.3% increase in total membership. The union's membership peaked back in 2002 when it represented nearly 700,000 automobile workers. The Department of Labor reported that total union membership in the United States has grown from 14.6 million workers in 2014 to 14.8 million in 2015.
See "Autoworkers Union Grew for 6th Consecutive Year", The New York Times, March 25, 2016