United States. Bureau of Labor Statistics. "National Compensation Survey: Chicago-Gary-Kenosha, IL-IN-WI, October 2006 : Bulletin of the United States Bureau of Labor Statistics, No. 3135-72," National Compensation Survey (Wages and Salaries) (July 2007). https://fraser.stlouisfed.org/title/6009/item/582984, accessed on September 11, 2024.