Sale 1:

https://backpack.tf/profiles/76561198389618559#!/compare/1566691200/1567036800

https://backpack.tf/profiles/76561198405507730#!/compare/1566950400/1567555200

SCM

sale 2:

https://backpack.tf/profiles/76561198405507730#!/compare/1570752000/1571616000

https://backpack.tf/profiles/76561198337734785#!/compare/1571529600/1571616000

QS

sale 3:

https://backpack.tf/profiles/76561198236425506#!/compare/1569542400/1569715200

https://backpack.tf/profiles/76561198101915413#!/compare/1569715200/1569801600

Untrace

sale 4:

https://backpack.tf/profiles/76561198101915413#!/compare/1569974400/1570060800

https://backpack.tf/profiles/76561198196410274#!/compare/1569974400/1570060800

untrace

sale 5:

https://backpack.tf/profiles/76561198196410274#!/compare/1569974400/1570060800

https://backpack.tf/profiles/76561198100015582#!/compare/1569974400/1570060800

Sold for DBD Gilded(15.5)

Sale 6:

https://backpack.tf/profiles/76561198100015582#!/compare/1570492800/1570579200

https://backpack.tf/profiles/76561198062205682#!/compare/1570492800/1570579200

Sold for Aces Chief

use there, ends up low here

Sale 7:

https://backpack.tf/profiles/76561198062205682#!/compare/1570492800/1570579200

https://backpack.tf/profiles/76561198120672630#!/compare/1570406400/1570579200

Bulk

sale 8:

https://backpack.tf/profiles/76561198120672630#!/compare/1572048000/1572134400

https://backpack.tf/profiles/76561198167418363#!/compare/1571788800/1572134400

Sold for C9 Oiled + ~4.5 keys in sweets

use there

sale 9:

https://backpack.tf/profiles/76561198168482362#!/compare/1563926400/1567296000

https://backpack.tf/profiles/76561198023051867#!/compare/1570060800/1570233600

SCM

sale 10:

https://backpack.tf/profiles/76561198023051867#!/compare/1570752000/1570838400

https://backpack.tf/profiles/76561198146608511#!/compare/1571011200/1571270400

Untrace

sale 11:

https://backpack.tf/profiles/76561198195960235#!/compare/1566000000/1566345600

https://backpack.tf/profiles/76561198195960235#!/compare/1566000000/1566345600

Untrace

Sale 12:

https://backpack.tf/profiles/76561198150930904#!/compare/1566777600/1566950400

https://backpack.tf/profiles/76561198278481498#!/compare/1566864000/1566950400

Bulky

Sale 13:

https://backpack.tf/profiles/76561198278481498#!/compare/1567036800/1567296000

https://backpack.tf/profiles/76561198071673857#!/compare/1567209600/1567296000

https://backpack.tf/profiles/76561198012537041#!/compare/1567382400/1567468800

https://backpack.tf/profiles/76561198148532116#!/compare/1567382400/1567468800

https://backpack.tf/profiles/76561198337734785#!/compare/1567382400/1567468800

Untrace

Sale 14:

https://backpack.tf/profiles/76561198337734785#!/compare/1567555200/1567641600

https://backpack.tf/profiles/76561198438389114#!/compare/1567036800/1567641600

Sold for 12 keys

Sale 15:

https://backpack.tf/profiles/76561198138664594#!/compare/1566432000/1566691200

https://backpack.tf/profiles/76561198293132410#!/compare/1562284800/1566950400

Untrace

Sale 16:

https://backpack.tf/profiles/76561198158351628#!/compare/1567728000/1568505600

https://backpack.tf/profiles/76561198145906987#!/compare/1554681600/1570233600

SCM

sale 17:

https://marketplace.tf/items/tf2/30045;5;u58

$19.99 / $1.81 = 11.04 keys

$24.64 / $1.84 = 13.39 keys <--- https://backpack.tf/item/7955874407

$29.99 / $1.82 = 16.48 keys

total sales @:

11, 12, 13, 15.5, 16 keys

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

Seller for 12 keys unsold for some time,

considering 15.5 resold for lower,

taking 11 - 13 keys, calling 15.5 + outliers.