Why not? I'm already better than 90% everywhere else. No joking. I don't even try that hard and I sill perform better than 90% at work compare to everyone else even people who's been there for 20 years.Sorry, "performance" is subjective. The point is many have average or a little above average results over time - that's the 70% in the middle. If you do a back-of-an-envelope calculation, factoring in traders' abilities and account sizes, it's obvious a career trader needs to be "better" than 90% to make a decent, consistent living.