Credit to Xergoyf B>QS for fixing this

Sale 1: Marketplace.tf sale, item goes to Marketplace.tf bot then gets withdrawn the the buyer's inventory

https://backpack.tf/item/7249660210 (Last seen in MP bot's inventory in July so it isn't any of the sales down below)

Sale 2: Sale at $33.33 on mp (August 15 2020)

https://backpack.tf/item/6462429966

Sale 3: 11 keys pure

https://backpack.tf/profiles/76561198063054044#!/compare/1594684800/1596067200

Sale 4: Deposit to mp (Current seller at $40)

https://backpack.tf/item/6480121276

Two valid sale on Marketplace.tf: https://marketplace.tf/items/tf2/30922;5;u3018

June 10 2020: $45.00 (median key price: $2.01, 22.39 keys) ~22 keys (untraceable)

June 15 2020: $31.00 (median key price: $1.99, 15.58 keys) ~16 keys (untraceable)

August 15 2020: $33.33 (Median key price: $1.81, 18.41 keys) ~18 keys (sale 2)

The sale at $33.33 took some time to sell and there's an unsold at $40, 22 keys is an outlier

Going with 16-18 keys