Back in the 70's my local library had a novel about a human coming to a human-colonized (I think) planet where mind control was common and where he was there to solve a crime. There was a hierarchy based on how many other people you could control, starting in the single digits and eventually going by tens up to eighty or so. The main character's local associate was something like a 40 working on 50, and our hero gets in trouble with his associate at one point for interrupting a mind duel he's engaging in on the road to 50.
Those in the single digits do most of the grunt work, though fortunately for our main character those who have no mind-control powers at all are exempt - he also chats with a "disabled" native at one point who is very glad to be disabled and out of all the competition.
Standard attire is a catsuit with your number over your heart, and what I remember most about the (hardback) book is the dustjacket, which depicted a woman who filled out her catsuit exceptionally well.
I have a vague recollection that the book was originally published in the 50's, but I wouldn't swear to it.