Helped by record U.S. auto sales and production increases, United Auto Workers membership rose by nearly 5,200 last year, according to the union’s annual filing with the Department of Labor.
The document showed total membership of 408,639, up 1.3 percent from 403,466 at the end of 2014.
It was the sixth straight year of growth for the UAW, but membership remains well below the peak of about 1.5 million in 1979.
Customers in the United States bought or leased a record 17.5 million new cars and trucks last year, up from 16.5 million in 2014. General Motors, Ford and Fiat Chrysler boosted production, adding jobs at plants where shifts were added or the production line speed was increased.
By the end of November 2014, the UAW completed negotiations on new four-year contracts with each of the Detroit Three. Those agreements narrowed the wage gap between those hired before and after 2007, preserved most of the health insurance benefits and provided substantial upfront signing bonuses for about 150,000 members at the three automakers.
But the union is still battling to gain a foothold in the dozens of nonunion plants owned by Asian and European automakers, which produce about 46 percent of new vehicles sold in the United States.
In Chattanooga, Tenn., the UAW won the right to represent more than half of Volkswagen’s hourly workers who have joined UAW Local 42. However, the union is not the exclusive bargaining agent and those members don’t pay dues.
The UAW has succeeded in organizing outside the auto industry, such as in higher education, primarily graduate teaching assistants, where it bargains for 25,000 workers.
The Labor Department filing also showed the union spent $709,000 last year on political activities and lobbying, down from $811,000 spent in those areas during 2014.