Twelve had falls of over 4.4% a year, which is the rate of decline that is needed to meet the millennium development goal (MDG) of cutting by two-thirds the child-mortality rate between 1990 and 2015 (see chart).
According to Mr Demombynes and Karina Trommlerova, also of the World Bank, 16 of the 20 African countries which have had detailed surveys of living conditions since 2005 reported falls in their child-mortality rates (this rate is the number of deaths of children under five per 1, 000 live births).
High-mortality Liberia actually saw impressive GDP increases whereas Senegal, whose record in childmortality is second to none, had a rather anaemic growth rate by recent African standards (3.8% a year, half that of Rwanda).