I am not surprised about the quite good numbers for LMAX and Interactive brokers, both are more or less aiming for more professional traders, which will do a little better
The Numbers for Darwinex are ok, but think about ... how many want to "try their luck" because of theDarwinIA and so on. I guess depending on how many new customers started trading, the number of winners can drop significant. But neither a good or bad value can tell the full story of whats going on.
Much more intresting would be lifetime performance (instead of fixed horizon lenght)- but most likely this % is even worse or/and percentages for different customer groups, depeding on their time already trading with the broker. (e.g <6month,>2 years, rest).