Josh P. Davis, a psychology professor at the University of Greenwich estimates the 1% of the population are "super-recognizers" of faces.
From Science Alert:
In 2009, a team of neuroscientists from Harvard did one of the first studies of super-recognisers. In it, they looked at just four people who claimed to have an unusually good ability to recognise faces.
All four subjects told the researchers about instances when they'd recognised practical strangers: family members they hadn't seen for decades or actors they'd glimpsed once in an ad and then seen again in a movie. They felt like there was something wrong with them.
One of the people in the study told the researchers that she tried to hide her ability and "pretend that I don't remember [people] … because it seems like I stalk them, or that they mean more to me than they d.".
I've always felt that I'm sometimes a super-recognizer and sometimes nearly face blind. I just took the five-minute online test. I scored 11 out of 14. My results said, "If you scored above 10 you may be a super recogniser, but you would need to do more tests to find this out."