Hakoreshejwe igipimo ca leta ya Afrika y'Epfo mu gupima ubukene - umuryango wose uronka umwimbu uri musi y'amadolari 55 ku kwezi - ibiharuro vyerekana ko hagati y'imyaka ya 2006 na 2011 ibitigiri vy'abari musi y'urwo rugero vyagabanutse, biva kuri 51% bija kuri 36.4%.
