As union membership has fallen over the last few decades, the share of income going to the top 10 percent has steadily increased. Union membership fell to 11.1 percent in 2014, where it remained in 2015 (not shown in the figure). The share of income going to the top 10 percent, meanwhile, hit 47.2 percent in 2014—only slightly lower than 47.8 percent in 2012, the highest it has been since 1917 (the earliest year data are available). When union membership was at its peak (33.4 percent in 1945) the share of income going to the top 10 percent was only 32.6 percent.…For "unions" substitute "labor bargaining power." In the view of neoclassical economics, trade unions that increase labor bargaining power are against the free market because they permit rent extraction to occur that would not occur if labor contracts were negotiated individually between "economic units," firms and individual workers being the units.
Economic Policy Institute
As union membership has fallen, the top 10 percent have been getting a larger share of income
Jessica Schemer and Lawrence Mishel