I don't know whether it's possible to do the maths, but it would be interesting to compare the ratio of number of personnel to number of aircraft operated for say, today and the late 80's when arguably the RAF was at it's strongest in recent times. Would this be an accurate measure of relative efficiency?
In the late 80's we had about 110,000 uniformed strength-how many aircraft did we operate? RAFG had about the same number of FJ Sqns that we have now, plus 11GP had 8 AD Sqns and 1GP had 4 GR4 Sqns, 3 Jag Sqns,2 Harrier Sqns plus the Bucc force. SH Force was slightly smaller, we had a maritime fleet and the AT/AAR Fleet was bigger. Add to this the other units like the Canberra fleet, SAR force as well. Don't forget that the entire training fleet (1FTS,2FTS,4FTS,6FTS and RAFC) was operated and largely engineered entirely by blue suits.
Remove the RAF Regiment from the equation as being a separate combat element (about 5 field Sqns? plus Rapier Sqns).
Compare that to the current uniformed strength/aircraft operated today. What would be the aircraft/personnel ratio and would this be an accurate measure of 'bang to buck'?