About 90% of my trades have been profitable ones. I've made approx. 30-40 trades on tradehill. Try flipping a coin 30-40 times and see how often you get 90% heads.
Since you're the one claiming it would be out of the ordinary, why don't you do the math
You of course know how to do basic statistical calculations.(PS: Traders talking about their success rates after the fact, using words like "about" and "approx" don't ever show up in scientific research. Can you guess why that would be?)