Sale 1:

https://backpack.tf/profiles/76561198072439676#!/compare/1564531200/1564617600

https://backpack.tf/profiles/76561198369477018#!/compare/1564531200/1564617600

untrace

sale 2:

https://backpack.tf/profiles/76561198369477018#!/compare/1564617600/1564790400

https://backpack.tf/profiles/76561198077827135#!/compare/1564531200/1564617600

Untrace

sale 3:

https://backpack.tf/profiles/76561198077827135#!/compare/1568678400/1570665600

https://backpack.tf/profiles/76561198805760331#!/compare/1570320000/1570406400

Untrace

sale 4:

https://backpack.tf/profiles/76561198805760331#!/compare/1570406400/1570492800

https://backpack.tf/profiles/76561198109506971#!/compare/1570320000/1570492800

https://backpack.tf/profiles/76561197999711055#!/compare/1570406400/1570492800

Untrace

sale 5:

https://backpack.tf/profiles/76561198987350303#!/compare/1571270400/1571356800

https://backpack.tf/profiles/76561198962171031#!/compare/1571270400/1571356800

Sold whit ~2 keys in sweets for G Fetti Elfin

Elfin Mini:

https://backpack.tf/suggestion/5dad5b77d38172047a3693b0

Suggestion for 10.25 keys

Total is ~8.25 keys

Sale 6:

https://backpack.tf/profiles/76561198962171031#!/compare/1571270400/1571356800

https://backpack.tf/profiles/76561198131081286#!/compare/1571011200/1571356800

Can trace a key

Sale 7, 8:

https://marketplace.tf/items/tf2/229;5;u29

$22.7 / $1.80 = 12.61 keys

$16.53 / $1.82 = 9.08 keys

Total sales @:

8.25, 9.08, 12.61 keys

poorly bumped seller for 12 keys,

buyers up to ~6 keys,

12.61 is an outleier,

taking 8.5 - 9 keys