I gotta go with 1% or fewer. Many people have bikes burried somewhere. If we count them all I'll guess it's far below 1%.
I'll bet
BengeBoy's guess on miles is about right too.
Skis? I WISH I could use mine more. But between gas and lift tickets (and wanting to ride) it's getting harder to get there.
The other thing that may relate to this quesion: My wife rides, but doesn't play tennis or ski. Guess what I'd rather do?