The UN data shows a very weak negative correlation between civilian gun ownership and national homicide rates. As Howard Nemerov points out, however, even this comes with a very significant asterisk:
Some of the most repressive regimes reported the lowest homicide rates. But since this data comes from law enforcement sources, it doesn’t include state-justified murder. For example, Syrian “security forces” recently killed “at least 20” civilians during one protest, but “Criminal Justice Sources” reported Syria’s homicide rate was significantly lower than America’s.
In Yemen’s capital of Sana’a, “soldiers and plain-clothed government loyalists” killed “at least 35” and left “hundreds wounded” after opening fire on protesters. The UN reports Yemen has a relatively low homicide rate.
At the extreme range is China, whose government declares “private citizens are forbidden from owning and selling guns,” and “gun crime is rare.” This policy allegedly protects “the safety of every individual citizen.” The official homicide rate appears to bear this out, but between 1949 and 1987 military and police legally murdered nearly 77 million. Today, China continues its heavy-handed response by imprisoning protesters for “inciting subversion of state power.”