Source: US. Bureau of Labor Statistics
Release: Consumer Price Index
US. Bureau of Labor Statistics, Consumer Price Index for All Urban Consumers: Professional services in Size Class B/C (between 50,000 and 1,500,000 persons) [CUURX000SEMC], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/CUURX000SEMC, December 10, 2016.