The steep decline in union membership in recent decades has had an outsize effect on the American workforce, tamping down wage increases for nonunion workers, according to a new study published just ahead of Labor Day.

USA Today reported Tuesday that the study from the liberal-leaning Economic Policy Institute found that the average weekly earnings for nonunion private-sector male workers would have been 5%, or $52, higher in 2013 if the share of union workers had remained at 1979 levels, That’s tantamount to a loss of $2,704 annually for the average nonunion worker.

The paper was authored by Washington University sociologists Jake Rosenfeld and Patrick Denice, and Jennifer Laird, a research scientist at Columbia University’s Center on Poverty and Social Policy.

Read the story here.