I'm about 35% done with the first draft now.
It's kinda hard to tell exactly at this point though ;) The average length for a novel is 100,000 words, so that gives me a rough gauge of my progress: 35,000 words equals 35%. Of course, since I haven't finished the first draft, I don't know exactly how close to done I am. The final story might be a bit over or under 100K words.