Club's ratings

Hi, i have a question. How is club rating calculated in Genie Scout? For example, I go on Club List, and there is club current rating and club potential rating. And let say Barcelona rating is around 77%...Real Madrid is behind with 76% on second place....and my club is 68%. I was just wondering how is that rating calculated, because when I change rating for players, that club rating doesn't change no matter what I change or edit in the players rating. So it must be calculated by some other formula then, I just wanna know how precise that formula is and what it takes in calculation, what aspects of a club team?

Thx in advance for your answers. GS the best tool definitely for FM!

Those club ca and pa are calculated on the average of every player in the club. So its simple statistics. If you change one player's of a total of 30 the average won't change.