The assumptions I'm making are that most people drink water and non water, and the non water they drink is not going to be more than 3 to 4 drinks (cups/bottles) per day, and that people drinking coffee are already filling their quota of non water drinks by drinking coffee so they don't drink sugary drinks.
The assumption is still that most people drink water during the day in addition to the coffee, and I'd think that is actually not the case. My experience is water is just an occasional drink during the day, not a primary drink.
