Another interesting case are ethnic Russians where 20 recurring men and women name (few pre-christian, and some christian) cover the bulk of a population of over 100m. I never found a satisfactory explanation why. What's more interesting is, my client was hiring branches of 20 employees, where you usually end up with 3 Olgas etc in one team, and people don't appear to be confused of who is meant when they say Olga.