Annex14,
Here's the relevant Wiki link in English:
http://en.wikipedia.org/wiki/World%2...ffic_movements
Your link was to the ranking of busiest by passenger movements, putting LHR at #4. The relevant figure here (in my opinion) is the number of total plane movements, which I linked to, with LHR at #13...both rankings put LHR as "busier" than JFK, but far behind other US airports.