Salem Kanoun Department of Economics, Associate Professor, Business Higher School (ESCT), University of Manouba   Campus universitaire de la Manouba Ecole Supérieure de Commerce de Tunis , Manouba 2010 Tunisia   kanoun@topnet.tn   http://www.esct.rnu.tn           JEL Areas: E6 : Macroeconomic Policy, Macroeconomic Aspects of Public Finance, and General C1 : Econometric and Statistical Methods: General