Serdar Ozkan U of Pennsylvania   3718 Locust Walk. Dept. of Economics Philadelphia, PA 19104 U.S.A   ozkan@econ.upenn.edu   www.econ.upenn.edu~ozkan           JEL Areas: E2 : Macroeconomics: Consumption, Saving, Production, Employment, and Investment: General (includes Measurement and Data) J3 : Wages, Compensation, and Labor Costs: General