StjepanM: I don't understand what this percentage means is it just for players who did it first try or for the ones that did it at all?
d4rkm4tter: It is the 1000 latest attempts of registered users on the problem. There are further rules to restrict the impact that a single user can make.
The sequence my previous comment referred to was: C2 D2 D3 E3 B1