All Employees: Professional and Business Services: Professional, Scientific, and Technical Services in Illinois was 434.20000 Thous. of Persons in March of 2022, according to the United States Federal Reserve. Historically, All Employees: Professional and Business Services: Professional, Scientific, and Technical Services in Illinois reached a record high of 434.20000 in March of 2022 and a record low of 247.80000 in October of 1991. Trading Economics provides the current actual value, an historical data chart and related indicators for All Employees: Professional and Business Services: Professional, Scientific, and Technical Services in Illinois - last updated from the United States Federal Reserve on April of 2024.