Ok, glad to hear the feedback. In my mind I always wondered since we're all working with smaller positions (and thus able to get in/out quickly)... whether the real studs amongst us should be able to actually *out-perform* the super-duper hedge funds, and therefore gross something in the 40%-50% range. It's comforting to know that the bar isn't quite that high.
I would guess 40-100% per year for successful, long-term daytraders during a 'normal' year, and perhaps 100-300% during exceptional years such as 2007 or 2008. As the account balances grow much larger than the size you mentioned, these percentage returns become very difficult without taking excessive risks (which is why hedge funds cannot typically achieve these kinds of returns).
I personally assume that it's assuming max "acceptable" leverage. Meaning, you can over-lever for short-term returns, but you'll eventually blow yourself up. If you manage to not blow yourself up, then you're using acceptable leverage.