Re: having been involved in this sort of malarkey....
It would be rather remiss of the security services if they weren't using the resources of Google and others.
The major commercial players have leading edge software and massive data capture as a matter of course, so are in a position to assess a large part of the internet relatively inexpensively. Google, for example, has been analysing net traffic to pick up hints of developing influenza epidemics for some while.
This is one reason why the NSA 1.6% figure may not be wrong, because other organisations are doing the pre-analysis for them. What is wrong is that no details of the arrangements are made public.