Re-suggesting, using sales from last suggestion onward.

Sales 1 & 2:

Sold for $22 and $11.99 on marketplace.tf

https://marketplace.tf/items/30840;5;u3004

22/1.98 = ~11.11111

11.99/1.97 = ~6.09

X = 11

X = 6

Sale 3:

Sold for 9 keys

Seller: https://backpack.tf/profiles/76561198044907142#!/compare/1532995200/1533168000

Buyer: https://backpack.tf/profiles/76561198301712661#!/compare/1533081600/1533168000

X = 9

Sale 4:

Sold for 9 keys?

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1532131200/1532217600

Buyer: https://backpack.tf/profiles/76561198815593082#!/compare/1532131200/1532217600

Untraceable. Bot.tf confirms, but bot.tf is unreliable. Couldn’t find key histories.

Histories show that it could’ve sold for the Fountain of Delight Bronco, but the ID’s don’t match. If I had to guess, I’d say the buyer sold the bronco to the bot, then bought the stagger from the bot.

X = 9?

Sale 5:

Sold for 8 keys

Seller: https://backpack.tf/profiles/76561198312583107#!/compare/1531353600/1531440000

Buyer: https://backpack.tf/profiles/76561198073037982#!/compare/1531353600/1531440000

Untraceable. Bot.tf confirms, but bot.tf is unreliable. Key histories below:

https://backpack.tf/item/6993583424

https://backpack.tf/item/6993583444

https://backpack.tf/item/6993583455

https://backpack.tf/item/6993583465

https://backpack.tf/item/6993583474

https://backpack.tf/item/6993583481

https://backpack.tf/item/6993583490

https://backpack.tf/item/6993583505

X = 8

Sale 6:

Sold for 8 keys

Seller: https://backpack.tf/profiles/76561198312583107#!/compare/1533686400/1533772800

Buyer: https://backpack.tf/profiles/76561198298670894#!/compare/1533686400/1533772800

X = 8

Sale 7:

Sold for 5 keys

Seller: https://backpack.tf/profiles/76561198086504479#!/compare/1533168000/1533254400

Buyer: https://backpack.tf/profiles/76561198116360626#!/compare/1533168000/1533254400

X = 5

Sale 8:

Sold to a bot for 5 keys + 5 ref

Seller: https://backpack.tf/profiles/76561198073037982#!/compare/1531526400/1531612800

Buyer: https://backpack.tf/profiles/76561198305676157#!/compare/1531440000/1531526400

X = 5

Sellers:

https://i.imgur.com/Xc5VAJD.png

~7.9 keys:

https://backpack.tf/item/6566253387

8 keys:

https://backpack.tf/item/6890707556

9 keys:

https://backpack.tf/item/5447066716

~13.43 keys:

https://backpack.tf/item/6431728486

Sales at:

5 (2x)

6

8 (2x)

9

11

And an untraceable sale at 9.

Going with 5-9, as requested by K1ng.