White to Non-White Racial Dissimilarity (5-year estimate) Index for Middlesex County, MA was 32.42% in January of 2022, according to the United States Federal Reserve. Historically, White to Non-White Racial Dissimilarity (5-year estimate) Index for Middlesex County, MA reached a record high of 37.36 in January of 2010 and a record low of 32.42 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 Middlesex County, MA - last updated from the United States Federal Reserve on May of 2024.