The US has only 4% of the world's population, but it possesses 46% of the world's civilian guns. Almost half of all the guns held worldwide by civilians are owned by US citizens.
There are about 7.5 billion people in the world as of 2020. The population of the US is about 330 million people, and the rest of the world about 7.2 billion people. The 330M US citizens own roughly 393 million guns, equal to 1.2 per person. The rest of the world's 7.2 billion people own 467 million guns, or 0.06 per person, about 1/20 the number of guns per person owned in America.
Source: Small Arms Survey 2018 https://en.wikipedia.org/wiki/Small_Arms_Survey