Where are these percentages coming from, OP? Afaik PSN doesn't give this information, only levels of rarity.
I assume psnprofiles.com.
While it doesn't represent the whole Playstation users as not everyone is registered there, I think it's still somewhat accurate as a sample.
They come from the PS4 system trophy menu. It shows not only levels of rarity but also percentage of players who got each trophy. So they are official numbers from Sony, and not from a third-party entity like psnprofiles.com