MCLEAN, Va. – Registered voters in Arizona, Colorado, Maine and Washington are voting today on ballot initiatives that seek to raise their respective state minimum wage rates, reports USA Today.

Four states on Tuesday will consider ballot initiatives to raise the minimum wage, threatening to widen the disparity between the growing number of jurisdictions that have lifted their pay floors and the rest of the country.

The news source says that Arizona, Colorado and Maine are seeking an increase in their minimum wage rates to $12 an hour by 2020; while in Washington, the rate would go from $9.47 to $13.50 an hour over the next four years.

USA Today writes: “A sweep would widen the gap between the 29 states—with 60% of the U.S. workforce—that now have base wages higher than the federal government’s $7.25 an hour, and the 21 states that remain at the U.S. minimum, according to the National Employment Law Project (NELP), a worker advocacy group.”

At least 20 states and dozens of cities and counties have approved gradual minimum wage increases in the past few years, while efforts to increase the federal minimum wage rate have been blocked in Congress.

“This is about states taking matters into their own hands,” Judy Conti, federal advocacy coordinator for the NELP Action Fund, told the news source. NELP says that about two million workers in the four states with ballot initiatives today would be affected by an increase in wages.

In an interview, U.S. Labor Secretary Thomas Perez says the “increasing divergence” among state minimum wages is intensifying the wage debate. “You shouldn’t have to win the geographic lottery to get access to a [higher] minimum wage,” he said.

Meanwhile, Michael Saltsman, research director for the Employment Policies Institute, suggests that higher minimum wages have prodded retailers and restaurants to reduce head count, and hire older and more experienced workers, which reduces opportunities for younger, less-skilled workers to enter the workforce. “You’re going to make it that much more difficult for people to find jobs at the bottom end of the career ladder,” he told the news source.

Earlier this year, California and New York approved minimum wage increases to $15 an hour by 2022, joining Seattle and San Francisco.