Resuggestion, thanks to Blaze for the info!

Sale 1:

https://backpack.tf/profiles/76561198093824611#!/compare/1549497600/1549584000

https://backpack.tf/profiles/76561198160856661#!/compare/1549584000/1549670400

https://backpack.tf/profiles/76561198093824611#!/compare/1550016000/1550102400

tradebacks?

sale 2:

https://backpack.tf/profiles/76561198047092983#!/compare/1554854400/1555113600

https://backpack.tf/profiles/76561198337734785#!/compare/1555027200/1555113600

QS

Sale 3:

https://backpack.tf/profiles/76561198127938353#!/compare/1550793600/1550880000

https://backpack.tf/profiles/76561198165635759#!/compare/1550361600/1550880000

Keys

Sale 4:

https://backpack.tf/profiles/76561198141832563#!/compare/1555027200/1555113600

https://backpack.tf/profiles/76561198118922746#!/compare/1555027200/1555113600

Sold for HG Elfin + 2 keys

Elfin Mini:

https://backpack.tf/suggestion/5cbc27d86780722235599456

Suggestion for 17.5 keys

Total is 19.5 keys

Sale 5:

https://backpack.tf/profiles/76561198118922746#!/compare/1555113600/1555200000

https://backpack.tf/profiles/76561198337734785#!/compare/1555027200/1555113600

QS for ~18 keys

Sale 6:

https://backpack.tf/profiles/76561198061489334#!/compare/1552780800/1552867200

https://backpack.tf/profiles/76561198337734785#!/compare/1552780800/1552867200

QS for ~18 keys

Sale 7:

https://backpack.tf/profiles/76561198098357074#!/compare/1554940800/1555113600

https://backpack.tf/profiles/76561198046921199#!/compare/1555027200/1555113600

Bulk

Sale 8:

https://backpack.tf/profiles/76561198098357074#!/compare/1554422400/1554508800

https://steamcommunity.com/market/listings/440/Unusual%20Deep%20Cover%20Operator

SCM

Sold for 61.33 CAD

Keys at 3.175 CAD

Total is 19.32 keys

Sale 9:

https://backpack.tf/profiles/76561198046921199#!/compare/1555286400/1555372800

https://backpack.tf/profiles/76561198002757046#!/compare/1555200000/1555286400

Sold for ~18 keys, QS

Sale 10:

https://backpack.tf/profiles/76561198154378057#!/compare/1552003200/1552262400

https://backpack.tf/profiles/76561198032131059#!/compare/1552176000/1552262400

Bulk

Sale 11-16:

https://marketplace.tf/items/30375;5;u60

$26.55 / $1.8 = 14.75 keys

$50.25 / $1.8 = 27.92 keys

$49.87 / $1.79 = 27.86 keys

$39.00 / $1.77 = 22.03 keys

$39.99 / $1.79 = 22.34 keys

$38.99 / $1.79 = 21.78 keys

Sale 17:

https://backpack.tf/profiles/76561198337734785#!/compare/1557100800/1557187200

https://backpack.tf/profiles/76561198028021218#!/compare/1556323200/1557187200

Untrace

Sale 18:

https://backpack.tf/profiles/76561198337734785#!/compare/1555891200/1555977600

https://backpack.tf/profiles/76561198311367185#!/compare/1554768000/1555977600

Sold for 19 keys

Sale 19:

https://backpack.tf/profiles/76561198080916711#!/compare/1558569600/1558656000

https://backpack.tf/profiles/76561198393588133#!/compare/1558483200/1558569600

Sold with ~5 keys in sweets for KaW Cannonballl

Cannonball Mini:

https://backpack.tf/suggestion/5cd710e2d38172403f5fc248

Suggestion for 21 keys

Total is 16 keys

Total sales @:

14.75, 16, 18, 18, 18, 19, 19.32, 19.5, 21.78, 22.03, 22.34, 27.86, 27.92 keys

Buyers up to 15 keys,

New / poorly bumped sellers at 21,

Blaze's Part:

2 additional marketplace sales at 22~ keys. should probably include 22 in the range here

taking 18 - 22 keys