Sometimes a picture really is worth a thousand words. Global Health Magazine posted this screenshot today.
The information used in this graphic comes from data assembled on the UNICEF site Child Info: Monitoring the Situation of Women and Children and collected between 2001 and 2007. The percentages above represent women aged 15–49 who responded that a husband or partner is justified in hitting or beating his wife under certain circumstances. See a chart with more country info and sources here.