I can only speak for South Africa, but these names are not reflective of the population at all. If you want to know the prevalence of names by % of the population, Stats SA is the authoritative resource.
https://www.statssa.gov.za/?p=16039
I can't tell from the page how the names were ranked on Forebears, but I'm curious about the methodology. It's incredibly difficult to establish naming trends for minority groups.