World Contraceptive Use 2011 provides the latest information available about contraceptive prevalence, by method, and unmet need for family planning for countries and regions of the world. Data on contraceptive prevalence and unmet need for family planning at the country level were obtained from surveys covering nationally representative samples of women of reproductive age. Detailed data on levels and trends of contraceptive prevalence and unmet need for family planning, including information on data sources, are presented in World Contraceptive use 2010. Estimates for the world and its regions are weighted averages derived by weighting the indicators for each country, extrapolated as needed to 2009, by the estimated number of women who, in 2009, were aged 15 to 49 and married or in a union.