Here's the interesting note, if you scroll down you'll see they broke down some of the countries into regions, looking at the US the highest rate was and still is in Washington, DC a city which has the strictest hand gun laws in the nation. Up until 2008 it was illegal for any private citizen to own a hand gun, a Supreme Court decision ruled the previous ban on hand guns unconstitutional and it was replaced by a strict set of regulations concerning the owning of a hand gun within the District.
However it is poignant to note that since the ban was lifted in 2008 the intentional homicide rate in DC has dropped to a record low, nearly half of what it was 10 years prior.