Anesthesia awareness: How often do people wake up during surgery?

The recent release of the new movie Awake, which tells the story of a guy experiencing "anesthesia awareness" (or waking up during surgery), has prompted some renewed attention to an issue that has existed since surgery and anesthetics were invented. The number of people that actually do experience some kind of consciousness during surgery is only about 0.1%, or about 21,000 people, in any given year. But that's still a lot of people, and thankfully it seems anesthesiologists are dedicated to getting that number as low as possible. But putting people "under" is an art really, because it's not something that can be measured specifically and the line between too little anesthetic and too much is a very narrow one.

Have you, or someone you know, every woken up in the middle of an operation? Scary!