Sami Kallal Higher School of Business, Manouba University, 2010, Manouba, Tunisia   Mohamed Ateb Street ,5031 Ksibet El Mediouni Ksibet El Mediouni, Monastir 5031 Tunisia   sami.kallal@yahoo.com             JEL Areas: E3 : Prices, Business Fluctuations, and Cycles: General (includes Measurement and Data) H6 : National Budget, Deficit, and Debt: General