And within the next five years, 17% of Americans will live in a state or metro area with a $15 minimum wage. For a visual timeline showing the pace at which cities and states plan to gradually increase the hourly minimum to $15, check out this Fortune graphic.

The increases on July 1 follow previously set guidelines approved by voters. New York City, Seattle, Mountain View, Los Angeles and the state California are all scheduled to incrementally reach a $15 minimum wage by 2022.

As more and more communities push for raising wages, debates about the economic impact of mandating a higher minimum continues. This week two studies about the effects of the wage increases in Seattle, the first city in the U.S. to introduce a $15 minimum.

A study from the University of Washington claimed that raising the minimum wage actually hurts low-income workers, but many experts on the topic pointed out flaws in the research methodology.

“There are a number of methodological issues that call the results of the University of Washington study into question,” said Ben Zipperer, economist at the Economic Policy Institute. “There is a large body of research that shows that modest increases in the minimum wage boost wages for low income workers without causing job loss, and nothing in the UW study suggests we should revise those conclusions.”

Josh Hoxie, director of the Project on Opportunity and Taxation at the Institute for Policy Studies, points out that the data used for the study excludes 40% of the Seattle workforce in a commentary piece that appeared on Fortune.

The other recent Seattle study, from researchers at the University of California-Berkeley, showed that wages in the restaurant industry increased and employment rates were unaffected.