White to Non-White Racial Dissimilarity (5-year estimate) Index for Williamson County, IL was 27.71% in January of 2022, according to the United States Federal Reserve. Historically, White to Non-White Racial Dissimilarity (5-year estimate) Index for Williamson County, IL reached a record high of 35.23 in January of 2011 and a record low of 27.71 in January of 2022. Trading Economics provides the current actual value, an historical data chart and related indicators for White to Non-White Racial Dissimilarity (5-year estimate) Index for Williamson County, IL - last updated from the United States Federal Reserve on May of 2024.