PS3 sales spiked 3750% upon restock at amazon

[NJ5]

PooperScooper said:
^ tech. yes. But you make 0 -1 so basically they sold an extra 3,750 units.

That's not how it works. Amazon calculates it like this:

Imagine an item was at ranking #3000, and then improves to #150. They'll show a percentage increase of 1900%, since:

(3000-150)/150 = 1900%

You can see some examples here, and confirm by yourself that it works the way I said:

http://www.amazon.com/gp/movers-and-shakers/books