Proportions of bike sales (categorized by frame material) for a prominent British bike company, i.e., Wiggle, according to a senior manager:
1. Aluminum
2. Aluminum, cont.
3. Carbon
4. Steel
5, Titanium
Those proportions are consistent with what you'll see on the sales floors of the vast majority of bike shops in the U.S., except that you'll see very few (if any) steel bikes and no titanium bikes.