Conservatives love to trash unions by saying they’re corrupt and do nothing but damage the economy. However, the progressive Economic Policy Institute put together a quick chart using data compiled from the U.S. Census Bureau, reported TruthOut. The EPI illustrated a strong correlation between the dwindling number of union membership and income inequality.

Researchers Colin Gordon, Thomas Piketty, and Emmanuel Saez noted that union membership has been on a steady decline since the mid-20th century. Union membership is now at its lowest since 1936, with only 11 percent of American workers being union members. During peak membership in the 50s, the country’s wealth was distributed more evenly throughout the population.

As TruthOut reported:

As membership increased after 1936 during the Great Depression, peaking at 33.4 percent in 1945 and staying about the same until 1960, the top 10 percent’s share of wealth fell. At a height of 46.3 percent in 1932, the share of wealth held by the richest tenth fell to 31.5 percent by 1944, remaining stable till about 1980. As union membership steadily declined after 1980, the wealthiest Americans saw their share of riches surge.

The main way that unions helped American workers get better pay was because unions gave those workers a louder voice in politics.

“Unions at midcentury also exerted considerable political clout, sustaining other political and economic choices (minimum wage, job-based health benefits, Social Security, high marginal tax rates, etc.) that dampened inequality,” said Gordon.

With unions, there really is power in numbers. American workers used unions to have their voices effectively heard by those in Washington. Now that union membership is at a near-all-time low, American workers aren’t being heard.