I wouldn't ask this question. The more you know the more you earn. In this kind of business, its all dependent upon your knowledge so do not ask how much but rather how much more can you learn. If you don't know much, its like trading blindly so make sure you're not trading blindly. You must continue to keep up with news and learn as much as possible as days go by if you want an extra advantage in the market.
As per my opinion, knowledge does matter but more important is the ability to introspect and rectify one's mistakes. A trader who is not willing to refine himself will never make even an iota of profit in the long run. The mistakes will continue to get repeated thereby resulting in losses which wipe down the account. Thus, I would knowledge only as a must have criteria behind strategy and discipline. Without proper strategy and discipline no amount of knowledge can lead a trader to success.