The AfDB's Chief Economist's department has created a Water and Sanitation Index of Development Effectiveness (WIDE). In a new economic brief, it reports that the overall rate of access in Africa to improved water sources had risen to 60 percent by 2008 compared to 49 percent in 1990.
The report notes that this equates to a marginal increase of less than one per cent annually.
Growth in access to better sanitation was more disappointing, according to the report. Over the same period, it increased to only 31 percent from 27 percent.
Access to improved water and sanitation is part of the Millennium Development Goals. Target 7C aims to halve the proportion of people without sustainable access to safe drinking water and improved sanitation.
However, the efforts and success of sub-Saharan countries are mixed, with some countries doing much better than others on the WIDE index.
The AfDB's analysis covered 45 of the total 48 sub-Saharan countries because reliable data was unavailable for the Seychelles, Djibouti and Somalia.
On the Watsan Index of Development Effectiveness, Angola came out on top. The countries taking the next highest four places, were Rwanda, Zimbabwe, the Central African Republic and Malawi.
The poorest performing country on the WIDE index was Equatorial Guinea, preceded by Madagascar in 44th place, Gabon in 43rd , the Republic of Congo at 42nd and Tanzania at 41st.
The report explains Angola's success due to 'the government's implementation of an aggressive capital investment program to expand and rehabilitate [the water and sanitation] infrastructure' together with institutional reforms put in place after a lengthy civil conflict.
On the Millennium Development Goals deadline, the report says 'though it is clear that there will be a shortfall in many areas, better monitoring of progress, and better understanding of the linkages of aid effectiveness, will make an important contribution to their overall achievement.'