1. Answer: It depends on everyone's taste and these rankings change all the time. According to RankMyPorn, at the moment, the top ranked Female Pornstars in the world are: Veronica Leal, Mia Malkova, Lana Rhoades, Sasha Grey, Kenzie Reeves, Kayden Cross, Elsa Jean, Riley Reid, Monique Alexander, Little Caprice, but these will change based on what people vote.
2. Answer: It changes. You can see the latest rankings on RankMyPorn.com and also vote on it for free.