There's no right or wrong answer here, surely? Although the fact that you are asking whether that amount is normal clearly shows that you're not that comfortable with it yourself. Nothing wrong with that either FWIW.
However, given that different people attribute different value to sex it stands to reason that there will be people who wouldn't want to be in a relationship who has had dozens of previous casual sexual partners in the same way that there are people who wouldn't want to be in a relationship with a virgin.
Also, there's a difference to judging someone from afar who has had multiple sexual partners, and judging from a relationship standpoint i.e. Not wanting to be in a relationship with someone who has a more casual sexual history.
Someone who views sex as part of a loving long-term relationship is unlikely to want to be with someone for whom sex is just casual, because they reach the point of wanting to sleep with someone when they know there are strong feelings on either side, whereas the casual sex person will essentially shag anyone who takes their fancy, and the long-term person doesn't want to be just "anyone" iyswim.
Similarly the casual sex person might not want a relationship with someone who has had minimal partners because they may feel under pressure to develop feelings and to give a value to sex which until now, they haven't felt.
I don't think that I would ask exact numbers but someone who had a long history of casual sex wouldn't be for me as I'm the kind of person for who sex needs to have meaning. Nothing wrong with them wanting to go off and have a lot of casual sex if that's what works for them,it just wouldn't be with me.