Union membership remained stagnant last year, according to a U.S. Bureau of Labor Statics report issued Thursday.

Because of that, a California financial advisor who specializes in working with unions says the growth of new members among his union clientele also has slowed.

Only 11.1 percent of wage and salary employees were members of unions in 2015, a figure that was unchanged from the previous year.

The number of wage and salary workers belonging to unions, 14.8 million in 2015, also was the same as the previous year. In 1983, the first year for which comparable union data is available, the union membership rate was 20.1 percent and there were 17.7 million union workers.

However, the median weekly earnings of nonunion workers, $776, were 79 percent of the earnings for union workers, which were $980.

Among the states, New York continued to have the highest union membership rate at 24.7 percent, while South Carolina came in last with only 2.1 percent. Some 7.2 million employees, or 35.2 percent, in the public sector belonged to unions, compared with 7.6 million workers, or 6.7 percent, in the private sector.

The financial industry is among private industries with a low union membership, 1.3 percent, while utility workers had a 21.4 percent membership and transportation and warehousing was at 18.9 percent.

J. Graydon Coghlan, founder and CEO of CFG Wealth Management in San Diego, specializes in representing union members. Although he has established a lucrative practice in this area, he warns other advisors that it is a difficult area to break into.

The number of new union clients has not grown significantly in recent years because there has been no growth in union membership in general or in union chapters, he says. Coghlan manages investment accounts for union members who are retired and also works with employees who have employer-sponsored accounts.