White to Non-White Racial Dissimilarity (5-year estimate) Index for Plymouth County, IA was 19.51% in January of 2022, according to the United States Federal Reserve. Historically, White to Non-White Racial Dissimilarity (5-year estimate) Index for Plymouth County, IA reached a record high of 40.52 in January of 2013 and a record low of 17.65 in January of 2021. 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 Plymouth County, IA - last updated from the United States Federal Reserve on May of 2024.