While the increase is modest as a percentage change, it is considerable in coverage when viewed as a net number. This reflects the high population growth rates in Arab countries and the importance of pursing water-related investments for increased service provision for the un-served as well as keeping pace with population growth trends.27 Figure 8 compares access to drinking water from the “piped on premises” source (or house connection), other improved sources and unimproved sources for the years 1990 and 2011. Despite the lack of complete data sets for all Arab countries, available national averages were used in calculating the regional average in order to compare and report on the progress of access to drinking water sources and sanitation facilities in the Arab region during the period 1990-2011. It is therefore important to highlight that the presented number of population with access to improved water sources and sanitation facilities at the regional level are approximate.