How about my 45% LF on routes with 60 pax and a 68 seat plane?
As you mentioned above, your RI on that route is 100, thus "all"
passengers that would travel the route (= all the demand) know you fly. If you have some competition, and their RI is also 100, they will take away the same amount of passengers as you do. So possibly, you are just facing some competition, eh?
Or you did too excessive pricing. That would just be guessing though.