No, snows and schooners have only two masts. Sloops usually have one mast, and although I've heard of sloops with two masts, I've never heard of one with three. Overlap, if it existed at all, would be negligible.
Of course, the word "ship" is often used in a more general sense for any large sailing vessel with multiple decks, but in that sense 97% of the vessels would be ships, not 45%.
as slight side note about schooners( i agree about snows though) schooners can have as many mast as you want as long as the forward mast (formast) is shorter than or the same height as the one behind it (mainmast), and they tend to be fore and aft rigged......just a little aside, for i work on a 3 masted schooner