Complex sentence: For 16 consecutive full seasons from 1996/1997 to 2011/2012, he never fell below 6th in the world rankings, and has been world number 1 on four occasions.
Split into simpler sentences: For 16 consecutive full seasons from 1996/1997 to 2011/2012, he never fell below 6th in the world rankings. He has been world number 1 on four occasions.