World Fertility Report 2013: Fertility at the Extremes is the fifth in a series and focuses on trends in fertility over the past 20 years and key factors underlying these trends for countries at the extremes of fertility: 66 countries with more than 3.2 children per woman in 2005-2010 and 70 countries with 2.0 children per woman or less in 2005-2010. The data presented are from World Population Prospects: The 2012 Revision, the official United Nations publication of population estimates and projections. Country data are taken from the same report, other United Nations sources or national sources, as appropriate.