Less than 1%. Depends on costs and practicalities of the whole thing though. And after I've said this, someone will come up with an online shop that sells 3D designs for printers, printing material, and makes it easily accessible and widespread to prove me wrong.. typical.

Anyways, there has to be some other use for it than "just for fun" and if most printers still cost close to $1000, I don't think so. However, if you could replicate spare parts for whatever with that 3D printer of yours, then that would be a killer product and I could see how it could still reach 1-10% by 2016. I don't think novelty values alone could take it that far though.