Originally Posted by JSWolf
Forgetting sales figures which nobody has to be definitive. We have more stores selling ePub, more readers able to handle ePub, we have more countries where we know ePub reins supreme. So it's fairly obvious that when you don't just mention the USA, that ePub has to be #1.
But the USA and UK combined, probably account for 80-90% of global eBook sales, and Amazon dominates in both those countries (in the UK more than in the US). That almost certainly means that they have over 50% of the world-wide eBook market.