Item 1

https://backpack.tf/item/13198004380

This history is just a trade back between two people

Item 2

https://backpack.tf/item/10955618229

Sale #1

Bulk transfer?-

Seller: https://backpack.tf/profiles/76561198983856237#!/compare/1683936000/1684022400

Buyer: https://backpack.tf/profiles/76561198097171432#!/compare/1683763200/1684022400

Item 3

https://backpack.tf/item/10765374661

sale #2

Untraceable-

Seller: https://backpack.tf/profiles/76561198839612863#!/compare/1686355200/1686873600

Buyer: https://backpack.tf/profiles/76561197984683993#!/compare/1690416000/1691020800

Marketplace.tf Sales

https://marketplace.tf/items/tf2/31224;5;u189

MP.TF Sale #1

Sold for $35 on May 12, 2023

Keys @ $2.04

35/2.04 = 17.16ish keys

MP.TF Sale #2

Sold for $35 on May 14, 2023

Keys @ $2.03

35/2.03 = 17.24ish keys

MP.TF Sale #3

Sold for $36.95 on August 3, 2023

Keys @ $1.95

36.95/1.95 = 18.95ish keys

MP.TF Sale #4

Sold for $36.95 on August 8, 2023

Keys @ $2.04

36.95/2.04 = 18.11ish keys

Sales @ 17, 17, 18, 19

Taking 17-19 here