I think this number is a lot lower than people may think. From personal experience I have had covid more than four times (not testing anymore), I was only actually symptomatic to any degree with the first one. By contrast, my partner has never once actually tested positive, despite certainly having it at least once, having caught it from me, and being very symptomatic. Some people shed a lot of the virus, and some people shed not any basically whatsoever, since the tests are based on actually shedding the virus, many people who simply don't shed the virus have caught covid-19 and simply don't realize it or won't ever test positive