Show This Chart To The Next Person Who Argues We Don't Need Unions

The decline in union membership in the United States has consequences reaching well outside the factory walls, among them: Fueling the rise of income inequality.

This chart, made by the Economic Policy Institute, a left-leaning think tank, shows the correlation between unions and income equality.

"The erosion of unions explains somewhere between a fifth and a third of the whole rise of inequality," Larry Mishel, an EPI economist, told HuffPost. "It especially hurts workers in the middle, and especially men."

To be sure, a host of other factors are contributing to the rise of income inequality in the U.S., including wage stagnation, rising health care costs, technological displacement and overseas competition.

As you can see, during the 1950's around 30 percent of Americans were union members and roughly 35 percent of American income went to the top 10 percent of earners. Today, only 11.3 percent of U.S. workers are union members, and nearly 50 percent of overall income goes to the top 10 percent.

Last week, unions took another devastating hit when workers at a Volkswagen plant in Tennessee voted not to unionize. The move, which many attributed to a blazing GOP campaign surrounding the vote, marked yet another new low for the labor movement.