I think the exact percentage, or more specifically the generations removed (away) from a wolf would be different for each CSV litter, unless a mating was repeated between 2 parents. Litters with lineage where an F1 was more recent (such as descendents of Kazan, I think) would maybe have a little more? There was a lot of line-breeding early on, so this would also have an impact.
Of course, specific genes are different within each puppy (just a like a human brother and sister with brown hair and blonde hair), even in the same litter, so the only real way to know would be to perform a DNA test on every CSV in the world.
