That also bumps up against the timeline laid out in Illinois’ constitution for approving new legislative maps. Senate President Don Harmon (D-Oak Park) says lawmakers shouldn’t wait on the new data, and instead start the process now, relying on other estimates, like the American Community Survey from 2019, and tweak numbers when the Census Data becomes available in six months. “Iowa is getting underway with its process,” Harmon told NPR Illinois Tuesday. “Oklahoma evidently is going to begin using the 2019 estimated data from the American Community Survey, which in the past has been a reliable predictor of the final Census data…We'll hear from [National Conference of State Legislatures] about best practices in other states, and hopefully find a path to follow.”