Prevalence of mixed infection and mean MOI over time. Years with fewer than 25 samples were merged with either the previous year or after, depending on the number of samples in that particular year. No samples were collected in 2001 and therefore data for this year was not presented. The bars represent 95 % CI while mean MOI error bars represent SD. For 1996–2000 and 2002–2008 periods, only history of SP use (case management or any dose of IPTp-SP) in pregnancy was documented while IPTp use was recorded for 2008–2009.