Credit to Zeussie for providing one of the sales

History 1: https://backpack.tf/item/1210716090

19 keys 5 ref:

https://backpack.tf/profiles/76561198297183050#!/compare/1618531200/1618617600

https://backpack.tf/profiles/76561198144346135#!/compare/1618704000/1618790400

Credit to Zeussie for the screenshot: https://prnt.sc/11pctde

Rounding to 19 keys

History 2: https://backpack.tf/item/553376134

Bulk to a backpack buyer:

https://backpack.tf/profiles/76561198321403116#!/compare/1610755200/1611100800

https://backpack.tf/profiles/76561198032176942#!/compare/1611100800/1611187200

Sold on Marketplace.tf: https://marketplace.tf/items/tf2/303;5;u40

January 22: $33.9/2.1=16.14 ~16 keys

This sold within a day

Given 16 sold within a day and it's really close to being outdated, should be fine to exclude that and go with 19 flat

One sold on Mannco.Store: https://mannco.store/item/29306

April 18: $60/1.83=32.79 ~33 keys

19-33 seems like a wide range, so I'll leave this up for a mod comment. After all, a lower value got excluded and it was closer to 19