I've noticed this as well, but perhaps those viewing already have their preferences set to view full size, and as such, it isn't recorded when viewed.  And that what you're seeing is those who have their settings default to resized, only when they choose to view full size that it's recorded.  Does that make sense?  I'd be awfully impressed if 70% of the users here opt to view reduced as opposed to full.

It might be a good question to ask in the Community Center.