Sale 1: Bulk

https://backpack.tf/profiles/76561198067991057#!/compare/1494633600/1494720000

Sale 2: Untraceable

https://backpack.tf/profiles/76561198041093177#!/compare/1497484800/1497657600

Sale 3: Untraceable

https://backpack.tf/profiles/76561198079955710#!/compare/1495929600/1496016000

Sale 4: Sold for Cauldron Bubbles Crocleather Slouch

https://backpack.tf/profiles/76561198111475184#!/compare/1495584000/1495670400

Being used to update the Slouch

Sale 5: Sold for Bubbling Company Man (17.5); rounding to 18 keys

https://backpack.tf/profiles/76561198260271932#!/compare/1493769600/1494028800

Sale 6: Untraceable

https://backpack.tf/profiles/76561198260271932#!/compare/1495152000/1495238400

Sale 7: 6keys pure; low. Compare link might be broken

https://backpack.tf/profiles/76561198113749386#!/compare/1497657600/1497744000

Sale 8: Bulk for Death at Dusk Shooter's Sola Topi

https://backpack.tf/profiles/76561198113749386#!/compare/1496448000/1496534400

Sale 9: Sold for Overclocked Hustler's Hallmark (15)

https://backpack.tf/profiles/76561198326403130#!/compare/1497916800/1498003200

Mini Hallmark: 15 keys https://backpack.tf/suggestion/59519eddcf6c755d896d535f

Sale 10: Sold together with Terror Watt Counterfeit Billycock (13.5) for Subatomic Universal Translator (30.5) --> 16 keys

https://backpack.tf/profiles/76561198306946843#!/compare/1495238400/1495324800

Mini Billycock: ~13.5 keys pure

https://backpack.tf/profiles/76561198211009049#!/compare/1493856000/1494028800

Sale 11: Untraceable

https://backpack.tf/profiles/76561198119283428#!/compare/1493769600/1494806400

Unsold 1 month

Sales at 15,16 18

Suggesting range from 15-18