The United Auto Workers union logo is seen on the front of the UAW Solidarity House in Detroit, Michigan, September 8, 2011. REUTERS/Rebecca Cook

NEW YORK (Reuters) - Membership in the United Auto Workers union rose by nearly 5,200 workers in 2015 to 408,639, the sixth straight year of small gains for the American union.

The Detroit-based union said in a filing with the U.S. Labor Department that membership rose 1.3 percent last year.

That is still down dramatically from the more than 700,000 members the UAW had in 2002 and from its all-time high of nearly 1.5 million members in 1979.

Since hitting a low of 355,191 in 2009, UAW membership has risen 15 percent.

A UAW spokesman did not immediately return a message seeking comment.

Last year, the UAW reached new four-year contracts covering about 150,000 workers with General Motors Co, Ford Motor Co and Fiat Chrysler Automobiles, four months after talks began.

The U.S. Bureau of Labor Statistics said in January that the percent of wage and salary workers who were members of unions in 2015 was 11.1 percent in 2015, unchanged from 2014.

There were 14.8 million workers in unions in 2015 in the United States, up from 14.6 million in 2014, the government said.