Sale 1:

https://backpack.tf/profiles/76561198197713293#!/compare/1552176000/1552780800

https://backpack.tf/profiles/76561198379270361#!/compare/1552089600/1552348800

idk

Sale 2:

https://backpack.tf/profiles/76561198379270361#!/compare/1553904000/1554076800

https://backpack.tf/profiles/76561198165205268#!/compare/1553904000/1553990400

~11 keys

Sale 3:

https://backpack.tf/profiles/76561198060405123#!/compare/1553904000/1553990400

Sold with some keys + Steaming Brown Bomber for Sunbeams Beanie, use there.

Sale 4:

https://backpack.tf/profiles/76561198042938501#!/compare/1553904000/1554076800

https://backpack.tf/profiles/76561198060405123#!/compare/1553990400/1554076800

qs

Sale 5:

https://backpack.tf/profiles/76561198110014232#!/compare/1554163200/1554422400

12 keys

Sale 6:

https://backpack.tf/profiles/76561198042919373#!/compare/1548201600/1549411200

https://backpack.tf/profiles/76561198360983155#!/compare/1545350400/1549152000

?

Sale 7:

https://backpack.tf/profiles/76561198154700747#!/compare/1550534400/1550620800

Lot of unus sold to scrap, idk

Sale 8:

https://backpack.tf/profiles/76561198142962201#!/compare/1550880000/1550966400

Sold with Terror-Watt Liquidator for GE Milkman, use on liq.

Sale 9:

https://backpack.tf/profiles/76561198142962201#!/compare/1551052800/1551225600

https://backpack.tf/profiles/76561198363395191#!/compare/1551052800/1551225600

who knows

Sale 10:

https://backpack.tf/profiles/76561198140429672#!/compare/1549497600/1554076800

11 keys + refs

Sale 11:

https://backpack.tf/profiles/76561198140429672#!/compare/1554076800/1554336000

idk

Sale 12:

https://marketplace.tf/items/434;5;u33

https://marketplace.tf/items/5021;6/Mann%20Co.%20Supply%20Crate%20Key

26$ on 30th of January

26/1.8=14.44 keys -> closer to 14 keys

Sale 13:

https://marketplace.tf/items/434;5;u33

https://marketplace.tf/items/5021;6/Mann%20Co.%20Supply%20Crate%20Key

24.5$ on 2nd February

24.5/1.81=13.53 keys -> closer to 14 keys.

Sale 14:

https://marketplace.tf/items/434;5;u33

https://marketplace.tf/items/5021;6/Mann%20Co.%20Supply%20Crate%20Key

26.99$ on 22nd of March

26.99/1.8=14.99 keys -> 15 keys

Sellers: 1 @ 14 keys

Sales: 11, 11, 12, 14, 14, 15

calling 15 an outlier, and going with 11-14 range.