Sale 1:

Sold with 6 Keys for Burning Mountain Cap

http://backpack.tf/profiles/76561198075816743#!/compare/1460764800/1460851200

x + 6 = 66

x = 60

Capped at B/O of 45 - http://www.tf2outpost.com/trade/28010629

Sale 2:

Sold for 45 Keys Pure

http://imgur.com/a/GiwQi

Sale 3:

Bulk for TF Muffs

http://backpack.tf/profiles/76561198068404730#!/compare/1459036800/1459296000

Invalid

Sale 4:

Bulk for Flies Mohawk

http://backpack.tf/profiles/76561198068404730#!/compare/1458284400/1458370800

Invalid

Sale 5:

Sold with Burstchester for Spec Aussie Rifle

http://backpack.tf/profiles/76561198147652029#!/compare/1458457200/1458716400

Rifle would have been around 36 back then

x + 4 = ~36

x = ~32

Outlier

Sale 6:

???

http://backpack.tf/profiles/76561198140431189#!/compare/1460160000/1460505600

http://backpack.tf/profiles/76561198177195049#!/compare/1460419200/1460505600

Buyers:

http://i.imgur.com/CVurYkD.png

x1 43 Keys

x1 34 Keys (I was buying at 31 previously)

Sellers:

http://www.tf2outpost.com/trade/28094636 - 50 Keys (~3 Weeks) - Declined 40 Pure

Conclusion:

Sales at 32, 45, 45. Calling 32 an outlier due to higher buyers and declined pure offers, taking a flat range of 45 Keys