Most things are explained inside the actual chart. Goal Contribution % is the the player's goals and assists/number of team goals when on the field of play.
The point of posting these numbers is to see if we can capture any trend, positive or negative, in the amount of Barca's offensive output that Messi has contributed to.
The trend here is pretty clear: amazing growth and increased contribution to Barca's offensive output for a number of years. But the growth was slowing by age 24 or 25. Contribution peaked at 25/26 and actual dipped last season.
Messi is posting a very strong 56% goal contribution number so far in 14/15. We must remember that although Messi has fallen from his own previous peak, his goal contribution numbers remain outstanding. It's just, you know, very likely that Messi's influence and contribution to this Barca offense has peaked. He is likely not improving anymore but actually regressing for a number of reasons. It is possible that we have already seen the very best years of Leo Messi.
He is, and will remain, an outstanding footballer who contributes at a truly elite level.
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