Read the passage below and solve the questions based on it.
India is supposed to send its boxing team for Olympics in each of the following 10 weight group divisions.
A (48 kg - 52 kg) B (52 kg - 56 kg)
C (56 kg - 60 kg) D (60 kg - 64 kg)
E (64 kg - 68 kg) F (68 kg - 72 kg)
G (72 kg - 76 kg) H (76 kg - 80 kg)
I (80 kg - 84 kg) J (84 kg - 88 kg)
After selecting one player from each group, their average weight comes out to be 68 kg. If one of the players named X leaves the team, their average weight comes down to 66.5 kg.
In the average of all the groups together, which group contributes most in overall average?