Estimate, Median Age by Sex, Total Population (5-year estimate) in Phelps County, MO was 36.00000 Years of Age in January of 2022, according to the United States Federal Reserve. Historically, Estimate, Median Age by Sex, Total Population (5-year estimate) in Phelps County, MO reached a record high of 36.10000 in January of 2009 and a record low of 33.70000 in January of 2011. Trading Economics provides the current actual value, an historical data chart and related indicators for Estimate, Median Age by Sex, Total Population (5-year estimate) in Phelps County, MO - last updated from the United States Federal Reserve on May of 2024.