Fun fact: People who decided to not take lessons are at a far higher risk to receive major injuries based on a recent study. This, like all accident/injury studies exclude collisions and park/pipe injuries.
That being said, I've been injured far too much snowboarding, but that's because I spend too much time in the park. Worst I've gotten was a sprained back that made it impossible for me to walk for 3 days, only time I've been sledded down.