If you need to see who sells the most houses as s lister, you would probably want to contact the local association of Realtors and they will have the data.
However, beware of agents that have the team concept, the numbers can be very inaccurate but I don't mean that they don't do a good job. I am speaking about the numbers only. I mean that sometimes an agent has the arrangement to have ALL the listings and sales go under one name but when there are several agents as many as 100 in that team.
I personally know an agent that self proclaimed himself "Top producing agent in Texas". Well, he is the broker/owner of the office and all the listings go under his name and sales as well. That is misleading when he hasn't even met most of the sellers or buyers. He can self proclaim to be "Top producing TEAM in Texas" though.