Bought it myself for 20 keys: https://backpack.tf/profiles/76561198202894547#!/compare/1616284800/1616371200

https://backpack.tf/profiles/76561198066220061#!/compare/1616284800/1616371200

Last owner bought it for 19: https://backpack.tf/profiles/76561199110809353#!/compare/1616198400/1616284800

https://backpack.tf/profiles/76561198202894547#!/compare/1616198400/1616284800

Untraceable: https://backpack.tf/profiles/76561198008009213#!/compare/1616025600/1616198400 - Probably sold for cash.

Untraceable: https://backpack.tf/profiles/76561197997384725#!/compare/1613174400/1613520000 - Probably bought from scm.

Bulk sale: https://backpack.tf/profiles/76561198088544779#!/compare/1612224000/1612656000

Bulk sale: https://backpack.tf/profiles/76561199110809353#!/compare/1615766400/1616112000

Sold for a Green giggler cauldron + green energy head hedge: https://backpack.tf/profiles/76561198069286674#!/compare/1613347200/1613433600

https://backpack.tf/profiles/76561198139695263#!/compare/1613347200/1613433600 - Outlier

Buyer sold for a PE energy head hedge: https://backpack.tf/profiles/76561198150072904#!/compare/1612915200/1613520000

https://backpack.tf/profiles/76561198139695263#!/compare/1613433600/1614297600

I will be excluding the PE and GE sale, considering that the buyer sold it for way less than what they bought it for.

Going for 19 - 20