Some points that you could clarify: You’ve shown data for number of guns per civilian population. What about data for fraction of population that owns (at least one) gun(s)? And the related question of the distribution of number of guns owned by individuals within the US compared to those in other countries (for example, perhaps guns in the US tend to be more concentrated with a certain unsurprising demographic whereas those in Switzerland may be more uniformly distributed, not to mention out-dated blunderbusses).
Also, re the claim of correlation between wealth and gun ownership, it would be interesting to see how that breaks down within the US.
Where do you get the raw numbers from, perhaps if I had access to the sources I could do my own analysis. I’m sure it has been analysed ad infinitum, but most articles I come across don’t have the micro-slices I think might be interesting.