interesting read. although your data suggest that, at the moment, sales are evolving linearly, that is not what I would have expected. From the speed the first 7M sold out, I would have guessed that it was a very fast start. We are now in a linear phase, but there could be some sort of saturation (most people spent what they intended) so I would expect a sigmoid curve and not a linear one. Have you tried to fit that to your data? Anyhow, interesting that there will be plenty of chances to buy some more packs :-).