Abderrazak Ben maatoug GEF-2A Lab, High Institue of Management, University of Tunis, Tunis   41, Avenue de Liberté Bardo, Tunis 2000   abderrazak.benmaatoug@isg.rnu.tn             JEL Areas: C1 : Econometric and Statistical Methods: General E5 : Monetary Policy, Central Banking, and the Supply of Money and Credit: General