Mouhamadou moustapha Ly CERDI and University Gaston Berger   65 Boulevard François Mitterrand Clermont-Ferrand, 63000 FRANCE   mouhamadoumly@yahoo.fr             JEL Areas: E6 : Macroeconomic Policy, Macroeconomic Aspects of Public Finance, and General G1 : General Financial Markets: General (includes Measurement and Data)