lot of Canon sport shooters went to Nikon when Canons keepers went down with the AF problems in the 1dmk3, the D3 was much better as a sport camera and Nikon followed up with D3s , compared to 1Dmk4. At the Olympic Games in Beijing there where many Canon shooters moving directly to Nikon because of the low keepers they got with 1Dmk3.
The lens line 14-24 , 24-70, 70-200 and 200-400 Nikon lens was also a big argument to move over to Nikon at this time. Nikon have increased the number of users from a few up to 50/50 in some events, Canon is still Nr1.
Funny, I CAN speak from experience. I shot the Big Ten track meet this year, and out of all of the sports photogs there, there was ONE Nikon shooter. Everyone else had a 1D Mark IV or 1Dx and ALL of them had a 400 f/2.8 for their primary lens.
there are a world larger outside than USA
Clutching straws ... Are we? The largest customer base for both cameras is in the US so the sample would be more than a fair representation. Anyway, I gave you the example from India as well.
As always though, we can agree to disagree and move on.
Cheers ... J.R.