State officials have never said exactly how much charity care is necessary for those tax breaks, but in 2010 the Illinois Supreme Court ruled that Provena Covenant Medical Center in Urbana should be stripped of its nonprofit property tax exemption for 2002 because the hospital didn't provide enough charity care—just 0.7 percent of its revenues that year. The Illinois Department of Revenue used the case in its justification for stripping three more health systems of their nonprofit status: Northwestern Memorial's Prentice Women's Hospital in Chicago, Edward Hospital in Naperville and Decatur Memorial Hospital in Decatur.