In Morrowind, the vast majority of NPCs were Dunmer. In Oblivion, Imperials had the largest part of the population, but there was a significant amount of other races. Although it makes more sense for it to be similar to be like Morrowind, it could really be any of the options.
The poll is pretty self explanatory, how do you want Skyrims population to be divided up? I want a large majority to be Nords, then a large population of Dark Elves, Redguards, Bretons, Orcs, and Imperials, and finally a small population of the remaining races.