Well on a recent DXB-LHR flight (744), which was pretty much full there were 26 passengers on board with emerald status, only one of whom wasn't a BA gold. Two of those 26 were GGL. All except three were flying in J or F.

I don't know how much can be extrapolated from this information but it may give an idea as to the make up of an average flight which is probably more interesting than total numbers of golds, etc.