Source: US. Bureau of Labor Statistics
Release: Consumer Price Index
US. Bureau of Labor Statistics, Consumer Price Index for All Urban Consumers: Utility (piped) gas service in Midwest - Size Class a (over 1,500,000 persons) [CUURA200SEHF02], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/CUURA200SEHF02, December 10, 2016.