http://i.imgur.com/eLJXbx2.jpg

Summer break is upon us

Sold for $35 in Marketplace(~17 Keys using 2.05 value)

https://marketplace.tf/items/30662;5;u97;strange

Sold with ~2 Keys in Sweets for a Cauldron Bubbles Bombing Run(16 Keys)(14 Keys total)

http://backpack.tf/profiles/76561198337869490#!/compare/1494979200/1495065600

Sold for an Orbiting Fire Big Elfin' Deal(12.5 Keys, round to 13)

http://backpack.tf/profiles/76561198323898208#!/compare/1493424000/1493510400

Sold for 11.5 Keys, Outlier

http://backpack.tf/profiles/76561198179306586#!/compare/1492473600/1492819200

Sold for 15 Keys?

http://backpack.tf/profiles/76561198109973821#!/compare/1487462400/1487808000

Nothing matches, leaving as supportive.

13-17.

Credits to Mindacos for finding the proof. All I did was make the actual suggestion.