Assaad Ghazouani LVPNC, FSJEGJ, university of jendouba   Jendouba, jendouba 8122 Tunisie   assaad.ghazouani@fsjegj.rnu.tn             JEL Areas: E2 : Macroeconomics: Consumption, Saving, Production, Employment, and Investment: General (includes Measurement and Data) C2 : Single Equation Models; Single Variables: General