Yes 88 weeks is the cutoff if you want to see every weeks details.... more than that and it goes up in 2s (always starting with week one)... I am not sure when it starts to go up in 3s but I would presume is is 176.
I have put this graph high enough so that it goes up in 5s, and thus catches the week 6 figures for NSMBWii... it may of course miss a couple of weeks off the end of Halo3 and MKWii but it doesn't make as much of a difference with older games as you can already see the trend:
http://www.vgchartz.com/swlaunch.php?reg1=All&game1=New+Super+Mario+Bros.+Wii+-+Wii[35076]®2=All&game2=Mario+Kart+Wii+-+Wii[6968]®3=All&game3=Halo+3+-+X360[6964]&weeks=288
Or the same graph of NSMBWii put against NSMB on DS and CoD:MW2 on 360:
http://www.vgchartz.com/swlaunch.php?reg1=All&game1=New+Super+Mario+Bros.+Wii+-+Wii[35076]®2=All&game2=New+Super+Mario+Bros.+-+DS[1582]®3=All&game3=Call+of+Duty%3A+Modern+Warfare+2+-+X360[28848]&weeks=288
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