Because Leon Cameron is clueless
In all seriousness, as
@freowho said, normally around 50% but dropped further - they seemed to of gone back to giving de Boer more time in there to tag the opposition's best mid (didn't work v Freo looking at Brayshaw's numbers).
Hopefully Leon can follow the lead of Rutten midway through last year with Merrett & get his best mid into the centre clearance rotations more. One of the many problems GWS currently have is even if they do win the centre clearance, look at the main mids who are then delivering the ball - Coniglio, Taranto, Hopper or de Boer. None of them are damaging/lack hurt factor - it was really eye opening on Sunday to see how often they burned teammates (especially Kelly), just lack composure with ball in hand. They are do not take advantage of the 6/6/6 rule from my viewpoint which I just can't understand.
Cameron is coaching for his career right now, anyone with half a brain knows that the most damaging mid he has is Kelly - he is the one guy who has composure, makes good decisions, executes well. It will be interesting to see what Cameron does over the next few weeks as clearly he needs to make changes fast before this becomes another wasted season for GWS.