Resuggesting! Thank you Lemons for letting me know that the other sales can be included now!

Item 1

https://backpack.tf/item/10938105464

Sale #1

Untraceable-

Seller: https://backpack.tf/profiles/76561199182453439#!/compare/1685664000/1686268800

Buyer: https://backpack.tf/profiles/76561199134395705#!/compare/1687910400/1688342400

Sale #2

Bulk or untraceable?-

Seller: https://backpack.tf/profiles/76561199134395705#!/compare/1688515200/1689984000

Buyer: https://backpack.tf/profiles/76561199084784906#!/compare/1689638400/1689724800

Item 2

https://backpack.tf/item/10349537356

Sale #3

Untraceable-

Seller: https://backpack.tf/profiles/76561198072995891#!/compare/1680220800/1684368000

Buyer: https://backpack.tf/profiles/76561198850121720#!/compare/1684368000/1684454400

Item 3

https://backpack.tf/item/10327186120

Sale #4

Bulk transfer?-

Seller: https://backpack.tf/profiles/76561199127652476#!/compare/1686528000/1686614400

Buyer: https://backpack.tf/profiles/76561198035132607#!/compare/1686873600/1686960000

Marketplace.tf Sales

https://marketplace.tf/items/tf2/31186;5;u180

MP.TF Sale #1

Sold for $35 on April 29, 2023

Keys @ $2.05

35/2.05 = 17.07ish keys

MP.TF Sale #2

Sold for $37.99 on July 25, 2023

Keys @ $1.95

37.99/1.95 = 19.48ish keys

MP.TF Sale #3

Sold for $37.99 on July 27, 2023

Keys @ $1.95

37.99/1.95 = 19.48ish keys

Sales @ 17, 19, 19

Taking 17-19 here