Counter, kinda. Excluding sales over 3 months, though.

The Sale:

Sold for 40 keys

https://backpack.tf/profiles/76561198380634252#!/compare/1721001600/1721174400

https://backpack.tf/profiles/76561198047609644#!/compare/1721088000/1721174400

https://backpack.tf/item/13068751414

= 40 keys

Other Sales:

#1

https://backpack.tf/profiles/76561199099468635#!/compare/1718841600/1719532800

https://backpack.tf/profiles/76561199097845692#!/compare/1719878400/1720051200

https://backpack.tf/item/13068751414

Untraceable, probably scammed or something

#2

https://backpack.tf/profiles/76561199097845692#!/compare/1720051200/1720656000

https://backpack.tf/profiles/76561198380634252#!/compare/1720569600/1720656000

https://backpack.tf/item/13068751414

Bulk for keys

#3

https://backpack.tf/profiles/76561198047609644#!/compare/1721088000/1721174400

https://backpack.tf/profiles/76561198045726608#!/compare/1720569600/1722124800

https://backpack.tf/item/13068751414

Untraceable

#4

https://backpack.tf/profiles/76561198136318095#!/compare/1719878400/1719964800

https://backpack.tf/profiles/76561198114402400#!/compare/1719878400/1719964800

https://backpack.tf/item/12936825767

Bulk for Purple Energy Flamehawk

#5

https://backpack.tf/profiles/76561198866241522#!/compare/1725321600/1725408000

https://backpack.tf/profiles/76561198045466865#!/compare/1725235200/1725321600

https://backpack.tf/item/13546842733

Backpack buy

Marketplace Sales:

https://marketplace.tf/items/tf2/31294;5;u18

$89.99, July 17th & 27th

https://marketplace.tf/items/tf2/5021;6

$1.71

$1.74

89.99/1.71 = ~53

89.99/1.74 = ~52

Sellers:

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

https://backpack.tf/item/13546842733 - 48 keys

https://backpack.tf/item/12936825767 - 50 keys

Sales at:

40

52

53

Seller at 50 has been there for a while, and the cheaper sellers further supports excluding the marketplace sales at 52 and 53.

Taking 40 flat.