Ive seen you count Robster. You better get a calculator for each hand.
Now I don't want to sound like I'm attacking you here Robbo, but whats the point of such a fact? The scoring this year is a totally different scoring scheme as to last seasons to begin with. Also, you may find that the quality of articles being presented has changed since the inception of the game, not to mention the fact that all the averages would be very similar, around 8.4 i'm guessing.
As willow said, its sounds like a lot of extra unneccessary work.
An overall average doesnt show how much a player may have improved and how good they are now. For example, say Robster average 4 in 2002, 6 in 2003 and 7 in 2004. His average would say he scores around 5.67 when in reality his last 2 seasons he's averaged more than that.
the same goes for form that has slipped. If you're doing it purely for curiousity reasons, then I suggest you do that privately. But if you want a true gauge of a writers scores, then take the previous season's average.