When the numbers of people who own firearms in the US is bandied about it should be recognized that if I (for example) own 10 guns, there are others who own none. This makes the total number of owned firearms (an estimate, of course) per 100,000 population (and similar comparisons) a bit questionable. For instance, if a figure of 88.1 guns owned per 100 people is used it does not take into account that some will own more than one gun and other will own none at all.

The University of Sidney (Australia) runs an interesting website regarding guns in 178 countries. It seems straight forward.