I have only 1300+hrs, not 13000 or 130000, but I can guarantee that if you separated out each of the ~ 50k factoids in the JAA IR paper study material (CAA approved FTO stuff), or each of the ~ 5k factoids in the JAA IR QB, and made two boxes, marked "relevant to flight, VFR/IFR, Europe or elsewhere" and "not relevant", a minimum of 90% would be in the latter.
Having now sat all 7 of the exams I am 100% confident of the relative proportions. It's nearly all garbage.
Speaking to old hands in this game, it's always been garbage, but maybe only 80% in the pre-JAA days.
It's a scandal, actually. Never in the history of human endeavour have so many clue-less pilots ended up in the RHS of a jet as today. When I read the latest AF447 instalment, it shocking not in that the pilots were such apparent FSX-drivers but in that they were still apparently just FSX drivers after a few k hours behind the Airbus FSX
If I wanted to dig out some clever formula, I use google.