Union membership in the US has plummeted from roughly a third in the mid-twentieth century to only 10.5 percent in 2018.9 This is a transatlantic trend. While a few countries retain high union density, among the developed nations of the Organization for Economic Cooperation and Development (OECD), the percentage of the labor force that is unionized has declined from 30 percent to 17 percent on average.10 This matters because, according to one estimate, the decline in unionization explains as much as a third of the growth in wage inequality.
