All Employees: Investigation and Security Services in Illinois was 40.10000 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, All Employees: Investigation and Security Services in Illinois reached a record high of 40.10000 in January of 2023 and a record low of 24.90000 in January of 1990. Trading Economics provides the current actual value, an historical data chart and related indicators for All Employees: Investigation and Security Services in Illinois - last updated from the United States Federal Reserve on April of 2024.