Sale 1:

Sold for 24 keys

Seller: https://backpack.tf/profiles/76561198320291083#!/compare/1534464000/1534550400

Buyer: https://backpack.tf/profiles/76561198122818049#!/compare/1534464000/1534550400

https://backpack.tf/item/4156042280

X = 24

Sale 2:

Sold for 22 keys + Haunted item (priced at ~10 ref, sellers/buyers significantly higher, counting it as higher than 0.5 ref)

No outpost

Seller: https://backpack.tf/profiles/76561198054139011#!/compare/1533081600/1533340800

Buyer: https://backpack.tf/profiles/76561198088728797#!/compare/1532736000/1533340800

https://backpack.tf/item/2983626055

X = 23

Untraceable/Unusable sales:

#1

Went to a private backpack

Seller: https://backpack.tf/profiles/76561198166908431#!/compare/1530921600/1531267200

https://backpack.tf/item/4195442745 - Buyer doesn’t match up here.

#2

Came from a private backpack

Buyer: https://backpack.tf/profiles/76561197960984512#!/compare/1532476800/1532736000

https://backpack.tf/item/4195442745

#3

Backpack transfer or something

Seller: https://backpack.tf/profiles/76561198105071091#!/compare/1532649600/1533427200

Buyer: https://backpack.tf/profiles/76561198320291083#!/compare/1533254400/1533340800

https://backpack.tf/item/4156042280

Sellers:

34 keys:

https://i.imgur.com/aCXqq2q.png

https://backpack.tf/item/4156042280

Sales at:

23

24

Going with 23-24.