Do we have any figures? How many copies sold? Would like to see the numbers for the PHB, Pathfinder, 4E, etc.
It would be great to see that.
Yes and no. I, too, am curious, but we would tend to attach meaning to the numbers that isn't warranted.
In order to really understand what the numbers imply, we'd need context over the years - and even if they gave us numbers for 3e and 4e, we'd have to then make adjustments for time, and economic situations around each release. In short - actually understanding sales numbers isn't trivial, and we'd be unlikely to do it well.