hello,
all depends on the trading strategy a trader will use. Percetange of success is always good to have but it can also be a little deceiving. Example: A client is losing 3 trades and winning 1. At the 3 lost trades he/she has losses as -5-5-5$. For the profitable one he/she has profit 20$. So, even the percentage of trades is not good for a client (won1,lost3), the trader has profit $5$ (-5-5-5+20). Therefore, at the end of the day a successful trader is the one who will have a positive outcome from (profits+losses). Of course, this example was just an exception.