I'm a third year. I didn't take USMLE though. There's no class statistics that I'm aware of. I'd guess that maybe 1/4 to 1/3 of the class took both tests. Honestly, I think you're putting the horse wayyyy in front of the cart if you're already thinking about taking both board exams. Get through the first two years of med school before you even stress yourself out thinking about that kind of stuff. Just remember that you're going to a DO school and already will be at a disadvantage applying for MD residencies (other than family med, psych, and peds). Unless you're in the top half of the class and killing it on practice tests, it probably wouldn't be worth your time to take it. Additionally, if you do poorly on it, you still have to report that you took it, so you can definitely shoot yourself in the foot. That's my two cents.