Easily available as epub/pdf. Who the hell reads a physical book anymore?
Considering Amazon still sells around 4 BILLION dollars in physical books in a year, I would say quite a few people. Roughly 30% of their book sales are ebooks.
In the world market, around 40 billion dollars in books are sold annually. Some analysts say upwards of 35% of those are now ebooks, but the most recent numbers suggest ebook market share might be slipping backwards.
A study was done recently to compare ebooks to paper books and ebooks were superior to paper in every aspect except one: people reading paper books tended to understand the content better than if they read it on an ereader. The irony of this result is akin to saying the British health system is superior to everyone else's in every measure except one: they don't actually save more lives than anyone else.
As for "easily available", I assume you mean via pirate sites. It is true that even content protection does not even slow down piracy and my own book has had more downloads on pirate sites than I ever sold on Amazon. It might bother me if I didn't know that people who steal rather than buy would never buy anyway, so at the very worst piracy can only result in more exposure. Perhaps some of my sales came from people who heard about my book through someone who pirated and read it. Just be careful, about 95% of the sites that claim to have these books for free are virus laden websites that will only get you infected.