On Wednesday, people across United States will partake in “A Day Without A Woman“—a national strike that encourages women to take off from paid or unpaid labor, abstain from shopping, and wear red in solidarity.
One of major goals of the event is to highlight the vital role women play in both the global and domestic economy. While it’s too soon to know the actual economic impact of the movement, the Center for American Progress has a projection: If all paid women were to take off on March 8, it could cost the U.S. almost $21 billion in Gross Domestic Product (GDP).
To come up with that number, analysts looked at the labor share of the GDP, and women’s relative pay and hours of work. Overall, they determined that women’s labor contributes a whopping $7.6 trillion to the nation’s GDP each year. But to further quantify women’s impact on a local level, the study’s authors also broke down what female residents of each state contribute to GDP per day. Working women in California and New York contributed the most, nearly $2.8 billion and $1.7 billion, respectively. Those in Vermont contributed the least, $36.8 million.
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“Women have long played a vital role in the economy, but women’s earnings and economic contributions are becoming more and more essential,” Kate Bahn an economist at CAP and co-author of the analysis, said in a statement. “However, due to occupational segregation and the devaluation of jobs that women disproportionately hold, outdated labor standards, and insufficient work-family policies, women in the United States aren’t able to meet their full economic potential.”
What’s more, if the GDP accounted for unpaid labor, (which is currently does not), the economic impact of all women refraining from all work on Wednesday would be far greater. For instance, women in the U.S. spend 150% more time on housework than men do, according to Bureau of Labor Statistics data, which the study notes. If this type of labor were taken into account, the U.S. GDP could increase by 26%.
“Take, for instance, the undervaluation of female-dominated jobs like school teachers, who affect the long-term productivity of children as they grow up and become workers themselves,” Bahn tells Fortune. “Or take the disproportionate amount of unpaid family care-taking duties women do, like making sure kids get to school happy and healthy in the first place.”
“Women’s contributions are even bigger when we think about the ways that aren’t measured by GDP,” she says.