Perhaps going by the "leaks" we know about we can have some idea? And as far as I know, almost all leaks point to the US doing the spying (and I would dare say

Perhaps going by the "leaks" we know about we can have some idea? And as far as I know, almost all leaks point to the US doing the spying (and I would dare say the EU spying agencies are much less competent, so proportionally there should be more leaks from EU spies than US spies - but that's not what we observe).