It's more general to "ebooks". FWIW, Kindle's make up a plurality of our e-book circulation, but we don't know the ratio of black and white to tablets. Anecdota

It's more general to "ebooks". FWIW, Kindle's make up a plurality of our e-book circulation, but we don't know the ratio of black and white to tablets. Anecdotally, we see a fair amount of Fire Tablets, but that could just be because people using Fire Tablets need more help. The survey I'm referencing (along with some other supporting data) is Pew, so take that for what it's worth.