Nobody knows the real numbers. There are threads which say anywhere from 85% to 99%. Real stats would be nearly impossible without an agreed upon set of definitions. Everyone (even the George Soros types) has a bad day, week, or month. Are they considers to be losers for that time? A newbie who goes "all in" could win 2 or 3 trades before slamming into a brick wall. Is this person classified as a "winner" for those first few days? If a trader had 2 methods being tested in 2 live accounts and one wins and one loses, do we call it even or compare the dollar (or percentage if the accounts don't have the same opening balance) to decide what category this person belongs in?
Here's one fact which should encourage you. A lot of people read about unlimited profits or buy some EA, education package, or trading method, fund an account with $100-$5000 dollars, and quickly blow their money. A large percentage of those don't come back.
On the other side, there are traders who either get the concept of risk management up front (or learn it the hard way), and then realize that the first key to success is not losing too much at any one time. They may run slight losses or be around breakeven for quite some time, but eventually will start to gain more than they lose.
Another way to think of it. How many people who take a foreign language as a college elective end up becoming highly fluent in the language? I'd guess it's only a few percent. The ones who stick with it and work at it over time have a much higher success rate than those who bought "Speak German in 10 minutes" course and quit after failing to have a perfect conversation the first few times.