Sale #1:

Probably sold on SCM to buy more crates

http://backpack.tf/profiles/76561198045890038#!/compare/1469750400/1469836800

Sale #2:

41 keys (outlier)

http://backpack.tf/profiles/76561198032609584#!/compare/1471132800/1471219200

Sale #3:

Duped Burning Western Wear (60) + '72 Buy A Life (38-40)

http://backpack.tf/profiles/76561198080179568#!/compare/1473984000/1474070400

http://www.tf2outpost.com/trade/28484573

I resold the Western Wear for 50 pure and the Buy A Life for either 36 or 37 CS:GO keys, this is easily over the B/O of 80 keys.

Sale #4:

http://backpack.tf/profiles/76561198214020751#!/compare/1475884800/1475971200 Sold with minor sweets for a CV Safe-n-Sound (72)

Should be close to 70.

Seller at 70:

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

http://backpack.tf/item/5005410026

GOING WITH 70-80 keys