Outdated + updating my previous suggestion with new data.

Proof based on a recent SCM sale: http://imgur.com/9o8TCGj

Purchased on SCM for 78.73 Euros = 35.46 keys (bought for)

35.46/1.15 = 30.83 keys (sold for)

So the range is 31 - 35 keys based on SCM sale.

As Foamy pointed out here http://backpack.tf/vote/id/56f03126b98d88295875a04f#comment-56f09fe9dea9e9b629c42c54

it was sold for a Pro KS Australium Sniper Rifle with parts, ~ 41 keys ( http://backpack.tf/profiles/76561198039007610/#!/compare/1458198000/1458284400 )

So the range is 31 - 41 keys.

Comments are welcome.