Reading a book is a journey, not a destination. Unless reading for you is like eating your vegetables not because you have developed a taste for them, but because you think it is "good for you," then why quantify it? Why stare at the odometer instead of enjoying the scenery and anticipating what may be ahead? Setting a goal of reading X number of books a year may be robbing you of the intrinsic rewards of reading itself.
Develop reading habits that carry their own rewards. Finishing so many books or pages in an allotted time could be detrimental. If reading becomes a chore for you, then you may be counter conditioning yourself. It could well be aversion therapy, and wouldn't that be a shame?
So, why start down the road of secondary rewards in the first place? I suspect that the answer lies in a faulty teaching strategy. We often try to encourage children to read by offering "pizza points" or some other bribe to read (or claim to read).
Open a book and step into a new world.