Tens of thousands of workers took to the streets in hundreds of cities across the country Tuesday calling for a $15 minimum wage.

The #Fightfor15 movement began in 2012 with a few hundred fast-food workers. By November 10, exactly a year before Election Day 2016, it had captured national headlines, with both Democratic front-runners tweeting their support for workers who marched in 400 cities, according to some estimates.

Backed by the Service Employees International Union (SEIU), Tuesday’s nationwide action saw home care workers and adjunct professors standing arm-in-arm with retail workers and restaurant employees demanding the right to unionize without fear of retaliation, and a hike in the federal minimum wage, which has been frozen at $7.25 an hour since 2009.

An estimated 42 percent of the U.S. workforce currently earns less than $15 an hour, a new report by the National Employment Law Project (NELP) found, with women and people of color vastly overrepresented in this demographic.

Female workers comprise 54.7 percent of those earning under $15 hourly, even though they account for less than half of the total workforce—48.3 percent—while African Americans, who make up just 12 percent of workers, represent 15 percent of low-wage employees.

Latinos are by far the most overrepresented, making up 16.5 percent of the labor force but comprising almost 23 percent of those earning less than $15 an hour. Nearly 60 percent of Latino workers and more than 50 percent of Black workers fall into the sub-$15 category of earners.

Rallies, walkouts, and strike actions held Tuesday highlighted links between racial and economic justice. The estimated 1,000 protesters who gathered outside the auditorium in Milwaukee, Wisconsin, where this week’s GOP debate was taking place, marched behind a banner that read, “Black Lives Matter. Immigrant Justice. Fight for $15.”

Despite protesters challenging Republican candidates to “come get my vote,” not one of the eight GOP front-runners offered support for higher wages in their responses to debate questions. An estimated 35 million Americans currently earn less than $10.55 an hour.

NELP research reveals that the leading industries for under-$15 hourly wages include food services, private households, agriculture, retail, and support services.

In food and retail services alone, a combined 7.7 million people take home less than $31,000 annually by some estimates.

Quoting statistics from the Bureau of Labor, the Pew Research Center puts the number of workers at or below the federal minimum wage at 3.3 million, the vast majority in food preparation and retail service industries.

The government calculates the annual income of a federal minimum wage worker to be $15,080, a figure that does not sit well with research from the Center for Poverty Research at the University of California, Davis, which puts the poverty threshold for a family of four at $22,283. The poverty line for a family of two is $16,078 according to the Economic Policy Institute.

Aside from fast-food workers, who form the core of the movement, care providers have been among the most vocal advocates for better pay. The vast majority of some two million employees in the home care industry are women of color.

Home care workers in Cleveland, Ohio, braved the rain outside City Hall Tuesday, while in San Diego, United Domestic Workers of America (UDWA) member LaTanye Cline addressed a huge crowd when she said, “Across California home care workers are joining the nationwide fight for $15. We won’t just sit back and watch while politicians and CEOs cut benefits for low-income workers while padding their own pockets.”

Tuesday’s actions coincided with a series of scattered but significant victories for the movement. Pittsburgh Mayor Bill Peduto issued an executive order requiring city employees to be paid at least $15 per hour, and called for legislation that would mandate contractors to pay the same by 2021.

New York Gov. Andrew Cuomo announced that all state workers would be guaranteed a $15 hourly wage by the end of 2018, marking the first time a governor has unilaterally mandated a wage increase for the entire state.