The number of PPLs (note: not PPL's - see
here 
) with current medicals is about 20k in the UK - the CAA have said so I believe.
Germany and France are (of the order of) the same size as the UK in the GA scene sizes, so that makes it say 60k for those 3.
I would bet anything that ALL the rest of Europe is less than those 3 countries combined i.e. perhaps
100k PPLs for all of Europe. Most of Europe has no real GA activity.