I think for the real number crunchers on the site paying a fee for being send the weekly sales data packages in a format of your choosing for you to play around with might be worth considering. I wouldn't take that up myself, but others might.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix