The minimum wage in St. Louis was rolled back on Monday from $10 an hour to $7.70, the statewide minimum, part of a broader trend of Republican state lawmakers pushing legislation that prevents local governments from setting their own labor law regulations.

Since the beginning of 2016, 15 states have passed 27 such local pre-emption laws, according a study released Monday by the liberal Economic Policy Institute, made possible by the GOP’s strong advantage in statehouses across the country. Republicans control 33 governorships and 67 of the 98 partisan state legislative chambers. In 24 states, Republicans have complete control, holding both the governor’s office and majorities in both state legislative chambers.