https://marketplace.tf/items/tf2/30479;5;u62

Sep 22 - $60 / $1.87 = 32.09 keys

Nov 27 - $59.99 / $1.76 = 34.09 keys

Dec 1 - $59.99 / $1.76 = 34.09 keys

Dec 8 - $59.99 / $1.74 = 34.48 keys

https://backpack.tf/item/3003646190

https://backpack.tf/item/3024364086

https://backpack.tf/item/3028227287

https://backpack.tf/profiles/76561198018055115#!/compare/1599955200/1600387200

https://backpack.tf/profiles/76561198986145947#!/compare/1599868800/1600387200

Bulk

https://backpack.tf/profiles/76561198986145947#!/compare/1599868800/1600387200

https://backpack.tf/profiles/76561198195933333#!/compare/1600300800/1600387200

Untraceable

https://backpack.tf/profiles/76561198195933333#!/compare/1600300800/1600387200

https://backpack.tf/profiles/76561198320774949#!/compare/1600300800/1600387200

21 keys

https://backpack.tf/profiles/76561198320774949#!/compare/1600300800/1600387200

https://backpack.tf/profiles/76561198079484723#!/compare/1600300800/1600992000

Untraceable

https://backpack.tf/profiles/76561198401143393#!/compare/1604102400/1604188800

https://backpack.tf/profiles/76561199004803157#!/compare/1604102400/1604188800

Untraceable

https://backpack.tf/profiles/76561198022309561#!/compare/1605398400/1605916800

https://backpack.tf/profiles/76561198164668247#!/compare/1605916800/1606521600

30 keys, the aus scattergun in the 2nd compare was sold so this was bought, so the history of the keys in the 1st compare matches to the scattergun

https://backpack.tf/profiles/76561198164668247#!/compare/1606521600/1606608000

https://backpack.tf/profiles/76561199085116273#!/compare/1606435200/1606521600

Untraceable

https://backpack.tf/profiles/76561199085116273#!/compare/1606521600/1606608000

https://backpack.tf/profiles/76561198091502579#!/compare/1606521600/1606608000

Untraceable

https://backpack.tf/profiles/76561198091502579#!/compare/1606608000/1606694400

https://backpack.tf/profiles/76561198068758470#!/compare/1606608000/1606867200

This looks like the December 1 Marketplace sale

https://backpack.tf/profiles/76561199015611823#!/compare/1604102400/1604188800

https://backpack.tf/profiles/76561199084784906#!/compare/1604102400/1604188800

Untraceable

https://backpack.tf/profiles/76561199084784906#!/compare/1604188800/1604275200

https://backpack.tf/profiles/76561198091502579#!/compare/1604188800/1604275200

Only 14 keys matches

Sales:

21

30

32

34

34

34

30-34