I'd say about 60/40 double/single, though I enjoy 2-handed more than single. I first bought a spey rod about 5 years ago, after tearing my rotator cuff, and I found I could at least keep salmon fishing with a two-hander, though not a pretty sight! Since then, my shoulder has pretty much healed, but have come to really enjoy the two-handers, and have decided to make a concerted effort to learn efficient technique. It sure feels good when I stumble into a perfect boomer single spey, but it's pretty rare. I've gone through a succession of rods, trying to find two or three 'keepers'.
Present sticks are Sage 9140-4 (my first spey rod), Winston 15' #10LT, Loop Yellow 13'2" 9/10, Hardy Salar 12'6" #9 (haven't gotten a chance to try this one yet), and a newly acquired T&T 1307 blank to be built shortly.
Favorite Single handers: Sage 890-3 SP, and an 896-2 SP
June: Newfoundland, Bay St. George, Robinsons, Crabbes, Middle Barachois: Smaller rivers, 2-handed only about 30%
July: Nova Scotia, Margaree R., 2-handed 60% or so, depending on water. Newfoundland, Portland Creek, Torrent R, River of Ponds, etc. : 2- handed 60%, then Labrador, Pinware R., 2-handed 80% (ahh can't wait!)
October (last week), Margaree, Middle, Baddeck, Cheticamp R.s: 2-handed 80% or more.
With the exception of the Margaree, I'm usually the only varmint around with a 2-handed stick, and get a lot of funny reactions from the locals, usually good-humored. It's always fun to hand it off to someone and let'm give it a whirl!