Complex sentence: In 1980, SFL changed its gate receipt sharing policy from 50:50 to 100:0 (which means home team gets all of the gate receipt), the number of attendance had been plummeted, approximately from 3.2 million to 2.5 million during 1980-1981.
Split into simpler sentences: In 1980, SFL changed its gate receipt sharing policy from 50:50 to 100:0 (which means home team gets all of the gate receipt). After changing the policy, the number of attendance had been plummeted, approximately from 3.2 million to 2.5 million during 1980-1981.