I once, loooong time ago, bought a book about "speed-reading". TOTAL waste of money.
I'm a slow/fast reader depending on what I read. I could probably read 100 books a year, but have no interest in that. I like to remember the contents of what I read.
Also, depending on the language of the book.
My native Norwegian goes generally twice as fast as English. Danish and Swedish, although mutually intelligible with Norwegian goes slower than English, d.t that it's not what I am "used to" read.
And, as mentioned; what's the contents of the book. Right now I'm reading a book obtained for free during the "read an ebook-week". Since it is normally a pay-book I force myself to read it as it was given to me for free, although it is not "my type" of book. And it is very slow, I'm only half-way through after 6 days..