Mohamed driouche Dahmani Department of economics at Djillali Liabes University of Sidi Bel Abbes, Algeria   ,   mohammed.dahmani@univ-sba.dz             JEL Areas: C3 : Multiple or Simultaneous Equation Models: General E2 : Macroeconomics: Consumption, Saving, Production, Employment, and Investment: General (includes Measurement and Data)