Monday is the deadline for all companies with more than 100 employees to report salary data to the federal government. Employers have been reporting demographic data about their employees to the Equal Employment Opportunity Commission for decades, but this will be the first year they’re required to add details about wages for a range of workers and to break those numbers down by gender, race and ethnicity.

It’s part of a push to address the persistent pay gap for women and minorities. On average women in the U.S. still make just 80 cents for every dollar earned by a man for the same work. The disparity is even bigger for women of color.

To tackle the problem, we have to see it clearly, said Emily Martin, vice president for education and workplace justice at the National Women’s Law Center. Having the hard data is important “because some employers think, well, if I don’t look at it, it’s not a problem I have to deal with,” she said. The information could be used to better enforce discrimination cases.

But the move has met resistance from many in the business community. Mark Wilson, vice president and chief economist for the HR Policy Association, said employers complain that it’s costing them millions of dollars to set up their reporting systems and that the data doesn’t account for all forms of employee compensation: “Health care benefits, the 401k benefits — all those types of things really aren’t measured,” he said.

This may be the first and last year employers have to meet the requirement, though. The Equal Employment Opportunity Commission has changed leadership under the Trump administration, and will no longer require the reporting in future years.