Sale 1:

https://backpack.tf/profiles/76561198309832044#!/compare/1603929600/1604016000

https://backpack.tf/profiles/76561198156272124#!/compare/1603929600/1604016000

= 17 Keys.

Sale 2:

https://backpack.tf/profiles/76561198156272124#!/compare/1604188800/1604275200

https://backpack.tf/profiles/76561198135406906#!/compare/1604188800/1604275200

= 18 Keys (?)

Sale 3:

https://backpack.tf/profiles/76561199016737637#!/compare/1603065600/1603152000

https://backpack.tf/profiles/76561198091502579#!/compare/1602979200/1603152000

Untrace / High

Marketplace.tf: https://marketplace.tf/items/tf2/30977;5;u33

Sale 4:

Sep 11 - $27 / $1.85 = 14.59 keys, No B/O

= 15 Keys. (QS)

Sale 5:

Sep 18 - $29 / $1.85 = 15.68 keys, No B/O

= 16 Keys.

Sale 6:

Sep 20 - $39.99 / $1.85 = 21.62 keys, No B/O

= 22 Keys.

Sale 7:

Oct 20 - $39.99 / $1.85 = 21.62 keys, https://backpack.tf/item/7125869449 (?) - No B/O

= 22 Keys.

Sale 8:

Oct 25 - $38.99 / $1.85 = 21.08 keys, https://backpack.tf/item/6833796798 (?) - No B/O

= 21 Keys.

Sale 9:

Oct 30 - $38.99 / $1.82 = 21.42 keys, No B/O

= 21 Keys.

Sales: 15, 16, 17, 18, 21, 21, 22, 22

Going with 16-22 keys.