Ah, hypnotism... I've always been interested in it, never really achieved any kind of deep state outside of sailing or playing BF1942, and neither are states that are terribly useful for the usual things people use hypnotism for...
Blip - funny, IIRC something like 90-97% of people can be hypnotised. Most of us enter a hypnotic state on a regular basis, such as when reading a book, playing computer games (for me, at least), watching TV (this is the whole principle on which commercials are based, that people are open to suggestion while watching TV... one more reason why I don't watch TV if I can help it), you get the idea.
But yeah, hypnotism is definitely a real thing... its effects date back to the work of (Francis?) Anton Mesmer in the 1700s IIRC, who was one of the first to apply the placebo effect on a mass scale (though he attributed it to 'animal magnetism' or somesuch) and probably date back way before that to the 'medicines' of the first tribal shamans (the majority of whose 'cures' relied on the fact that most ailments are either psychosomatic or self-healing, or can be healed through suggestion... for a modern example, read James Randi's The Faith Healers
and/or get a subscription to the Skeptical Inquirer). Richard Feynman gives an account in Surely you're Joking
of his experience with a stage hypnotist that's quite similar to Andrzejpw's, though a bit more detailed.