Done by TheProcave, posted with permission.

Steaming Gentleman's Gatsby - Micro for C9 Katyusha

Sale 1

https://backpack.tf/profiles/76561198337734785#!/compare/1572048000/1572134400

https://backpack.tf/profiles/76561198345192210#!/compare/1572134400/1572912000

Nothing found.

Sale 2

https://backpack.tf/profiles/76561198050518375#!/compare/1576281600/1576368000

https://backpack.tf/profiles/76561198374038715#!/compare/1576108800/1576281600

Ditto.

Sale 3

https://backpack.tf/profiles/76561198374038715#!/compare/1576627200/1576713600

https://backpack.tf/profiles/76561198271943742#!/compare/1575763200/1576713600

????

Mptf sales

https://marketplace.tf/items/tf2/184;5;u36

https://backpack.tf/item/1435573912

https://backpack.tf/item/1106524784

Sold for 13.89$ on the 3rd of November.

$13.89 / $1.79 = 7.76 keys, rounding up to 8 keys.

Sold for 15.53$ on the 8th of November.

$15.53 / $1.79 = 8.68 keys, rounding down to 8.5 keys.

Sales are at:

8

8.5

Taking the range as 8 - 8.5 keys!