From the Washington Center for Equitable Growth:

The labor market, for example, has seen the rise of several trends that have reduced competition in the labor market, to the detriment of many workers. In fact, the Obama administration has raised concerns about two little-known but increasingly prevalent labor market institutions: occupational licensing, and non-compete agreements.

Occupational licensing refers to the requirement that workers in certain occupations must get a license before getting a job. According to a report from the Treasury Departments Office of Economic Policy, the Presidents Council of Economic Advisers, and the Department of Labor, about 25 percent of American workers need a license to do their jobs. That share has increased by roughly 400 percent since the 1950s.