Apologies for the delay in replying to this, but hopefully this belated explanation will help:
First, it is important to remember that the percentages in the game are used as the basis for the goal numbers you can see in the different leagues. As a result, there is a degree of inaccuracy when it comes to the percentages shown in the game. As an example, if we assume that 50% of all players are at 2.3 goals or more, the result could be that only 47% of the players get sorted into the amateur league, as the goal target is set at 3 goals. This effect can also be seen in the other leagues, but it is less pronounced there as more goals are present that allow for a finer allocation.
We have designed it this way to make sure that there are clear goals for our players to strive for. Thanks to that, we avoid situations where, for example, the Bronze league requires 2.3 goals in one hour and 2.6 goals in the next, which would be frustrating and hard to see from the game itself.
Also, please remember that the players in higher leagues are not excluded when it comes to the calculation of the percentages, but the total number of players is used for the calculation of each league separately. This may contribute to the impression that some of the leagues are calculated wrong or have too few or too many players in them, which is not the case.
Now, why are some leagues unexpectedly empty then? Well, this is because the system is, in fact, a little bit more generous than you may expect. So, the gold league will actually round up a bit – meaning that Gold will have at least 1% of the participating players, Silver and Gold will be at least 5%, Silver, Gold and Bronze will be at least 20% and Silver, Gold, Bronze and Amateur will be at least 50%. All those leagues can have more than their associated percentage, as the system will set the goal thresholds lower than the percentage if it doesn’t hit on a round number. So, this behaviour is a result of players getting sorted a league higher than they otherwise would’ve been.
We can see that the way it works has created some confusion. Should we go for a similar league system in one of our future events, we will try making its behaviour clearer.