Ulrich jeanin aymar Ganga zandzou Faculty of Economic Sciences and LARES, Marien Ngouabi University   2155 rue voula Batignolles Brazzaville, Brazzaville 69 Republic of Congo   jeanin.ganga-zandzou@umng.cg             JEL Areas: G1 : General Financial Markets: General (includes Measurement and Data) O5 : Economywide Country Studies: General