The US in land area like I said is about the size of the entire continent of Europe. A lot more territory to cover. About half the population. So add the murder rates of every European country, halve it, then you have comparable numbers to the US. Canada has fewer people than the state of California. Australia even less. UK has a couple states combined.
As you can see the numbers don't really scale well. Most countries you like to use as examples aren't comparable as they don't have near the same type of variables.
