For the most part, no one carries guns around. In the US, some 3%ish of the population has concealed carry permits. (In some states, permits are not required at all, but the overall percentage won't be hugely higher.)
Since some very populous states, including #1 California and #4 New York are mostly no issue, the percentages are even greater in the 43 Shall Issue or better states, a number are getting up to 10%. The percentages are even greater when you adjust to the age eligible population.
So quite a bit higher than "no one", although of course having a licence does not equal routinely or always carrying.