BOSTON – An estimated 464,000 Massachusetts workers counted themselves as union members in 2018, the most since 2009, according to new federal data.

The U.S. Bureau of Labor Statistics reported that union members accounted for 13.7 percent of wage and salary workers in Massachusetts last year.

The U.S. average was 10.5 percent. Federal data shows there were 476,000 union members in Massachusetts in 2009, the highest level in recent years, and union members accounted for 16.6 percent of the employed workforce that year.

Eight states had union membership rates below 5 percent in 2018 – North Carolina, South Carolina, Utah, Texas and Virginia.

Two states had union membership rates over 20 percent in 2018: Hawaii and New York.

More than half of the 14.7 million union members in the U.S. last year lived in California, New York, Illinois, Pennsylvania, Michigan, Ohio, and Washington.

In Connecticut, 16 percent of workers were union members, down from 17.5 percent in 2016, according to the data.