First up I found out population figures for each city or town, then divided it by the number of attendees for the eleven home games they hosted. That produced a percentage that theoretically quantifies how well supported they are in relation to the size of the town or city.
I will explain the chart below. The first column is the ranking based on the percentage of people that come to their games. The second is the club, the third the population, the actual percentage achieved, the average number of spectators per match and finally a ranking number based on the average.
A couple of provisos. The Hull population figure is half of the city, seeing as Hull KR is also there. I don't know if dividing the city exactly in half reflects the support each club gets. If anyone can clarify that, please do so. Second, the Leeds club is named after the city but there are other clubs there. However, there is only major RL club in the so decided to keep the population figure as it is.
Not surprisingly, the largest population areas generally have the lowest percentage. As for achievers, Cas' is amazing and Wigan too. I didn't have any surprise with Salford and Huddersfield. I didn't know what the size of Perpignan was and its not as large as I thought. The catchment area for Catalan is an unknown for me. I thought Wakefield might have been a little higher.
Overall many of those attendances represent a high percentage of the population. I think many NRL clubs would be envious at some of those numbers. The well supported Brisbane Broncos get 1.4%. it's not an exact science but if taken as indicative of support, it does say something useful.