I can skim really quickly, but at that speed I'm actually reading subconsciously, I can't really recall the words, but I know what it said. However, my average reading speed is somewhere around 100 pages an hour.
But I would definitely say that I've had a couple reasons for reading as much as I have. My parents taught me to read before kindergarten (which IIRC I went into when I was 3, because we have 2 years of it sometimes). I was such a good reader by then that none of the shitty books they had interested me, because I'd read them once and get bored. The other part is that when I was being bullied and shit in school, part of my way of dealing with shit wa escapism, and I could manage to lose myself in a book in such a way that I was completely occupied by the book, and didn't have to think about schol, and all that shit. So there are really 2 primary reasons I read so much.
However, since then, I've come to really enjoy reading without using it as a form of escape. Unfortunately, I'm rather picky about stuff I read. If it's fantasy, it has to conform to what I want very heavily. It can't be any of those shitty fantasy books aimed at "young adults" or teenagers, it has to be a completely serious, well written story with characters that aren't childish and preferably a complex plot. It also has to be long. Half the time I pick up a new series, it's either because the books were huge, or because the plot sounds interesting. And by interesting, I mean complex and most likely involving some form of magic that isn't simply "Oh, I can cast spells".