Totally not surprised. And I do believe I can hear the shrieks, mantras of denial and beating of fists all the way over here. . .
Well at least one mantra of denial comes from an avid PF fan, yours truly.
"The charts are based on
interviews with retailers, distributors, and manufacturers." Which I read as "
we didn't bother even with pulling numbers out of 

, we just asked a question we won't bother to repeat, so people won't be able to question the methodology".
I mean, I find this believable, but with a grain of salt I applied? Tells me two things I didn't know already: one is jack, the second you can guess. Pathfinder was a large success that caught many off-guard. I wouldn't be surprised if, in reality, it's far in the second place, which is still a lot better than what most people anticipated, which in turn makes retailers mention it more often.
Besides, if it was true indication of sales? With Paizo selling it's product directly, and most successful ones via subscription - it'd mean they are in first place.
Which, with all my love for the system - I just do not believe. Not with 4e marketing, availability, brand etc.