The Range value is that between the average and the #20, on the assumption that the top 20 are unrepresentative. Given the sample size, that's open to debate. (If you fel strongly enough to argue, just post your own version)
It's interesting to note that the average ratings are in the same order, though it's very close with the last three.
(ocultar) Si deseas jugar una partida contra un adversario de nivel similar, puedes definir en tu invitación de nueva partida un rango BKR apropiado a tu interés. En tal caso, nadie con un BKR fuera de dicho rango podrá ver o aceptar la invitación. (Katechka) (mostrar todos los consejos)