Marjene Rabah gana Higher Institute of Commerce and Accounting of Bizerte   20, Rue Akhtal. El Menzah 1 tunis, Tunisia 1004 Tunisie   gana.ym@gnet.tn             JEL Areas: G1 : General Financial Markets: General (includes Measurement and Data) E6 : Macroeconomic Policy, Macroeconomic Aspects of Public Finance, and General