Resuggestion, thanks to polar for the info!

Sale 1:

https://backpack.tf/profiles/76561198026659447#!/compare/1543536000/1546992000

Untrace

Sale 2:

https://backpack.tf/profiles/76561198082282027#!/compare/1541721600/1547596800

https://backpack.tf/profiles/76561198084661970#!/compare/1545696000/1546214400

SCM

Sale 3:

https://backpack.tf/profiles/76561198084661970#!/compare/1546992000/1547251200

https://backpack.tf/profiles/76561198070018257#!/compare/1547164800/1547251200

Sold for 20 keys

Sale 4:

https://backpack.tf/profiles/76561198126970215#!/compare/1540771200/1547596800

https://backpack.tf/profiles/76561198019116055#!/compare/1529625600/1545436800

SCM?

Sale 5:

https://backpack.tf/profiles/76561198394244659#!/compare/1545782400/1545868800

https://backpack.tf/profiles/76561198061440669#!/compare/1545782400/1545868800

QS?

Sale 6:

https://backpack.tf/profiles/76561198147267309#!/compare/1541376000/1542672000

https://backpack.tf/profiles/76561198061440669#!/compare/1541462400/1541548800

Untrace

Sale 7:

https://backpack.tf/profiles/76561198061440669#!/compare/1541635200/1541721600

https://backpack.tf/profiles/76561198024832603#!/compare/1541116800/1541721600

10 keys?

Sale 8:

https://backpack.tf/profiles/76561198024832603#!/compare/1541894400/1542153600

https://backpack.tf/profiles/76561198161404359#!/compare/1542153600/1543536000

Untrace

Sale 9:

https://backpack.tf/profiles/76561198161404359#!/compare/1543795200/1544400000

https://backpack.tf/profiles/76561198169860395#!/compare/1543449600/1544400000

Untrace

Sale 10:

https://backpack.tf/profiles/76561198169860395#!/compare/1545696000/1546387200

https://backpack.tf/profiles/76561198410841638#!/compare/1546128000/1546387200

Sold for KaW Ushanka + ~14 keys in sweets

End up over sellers.

Sale 11:

https://backpack.tf/profiles/76561198095328347#!/compare/1546214400/1546992000

https://backpack.tf/profiles/76561198126985704#!/compare/1546905600/1546992000

Sold with ~5 keys in sweets for Strange version

Sale 12:

https://backpack.tf/profiles/76561198126985704#!/compare/1547078400/1547164800

https://backpack.tf/profiles/76561198384721099#!/compare/1547164800/1547251200

Sold for 22 keys

Sale 13:

https://backpack.tf/profiles/76561198384721099#!/compare/1547510400/1547596800

https://backpack.tf/profiles/76561198080179568#!/compare/1547510400/1547596800

Untrace.

Sale 14:

https://backpack.tf/profiles/76561198021055079#!/compare/1541030400/1541116800

https://backpack.tf/profiles/76561198301575831#!/compare/1541030400/1541116800

Sold for Bubbling Noble + ~12 keys in sweet

End up over sellers.

Sale 15:

https://backpack.tf/profiles/76561198451172915#!/compare/1545782400/1545868800

https://backpack.tf/profiles/76561198061440669#!/compare/1545782400/1545868800

QS?

Sale 16:

https://backpack.tf/profiles/76561198061440669#!/compare/1547164800/1547251200

https://backpack.tf/profiles/76561198070357404#!/compare/1513641600/1547424000

Untrace

Sale 17:

https://backpack.tf/profiles/76561198096856475#!/compare/1543622400/1543708800

https://backpack.tf/profiles/76561198060616510#!/compare/1543622400/1543708800

22 keys, probably.

Sale 18:

https://backpack.tf/profiles/76561198060616510#!/compare/1543708800/1543881600

https://backpack.tf/profiles/76561198034095893#!/compare/1543190400/1543881600

Bulk

Sale 19:

https://backpack.tf/profiles/76561198034095893#!/compare/1544659200/1544918400

https://backpack.tf/profiles/76561198083774393#!/compare/1499212800/1546732800

Sold for 25 keys

Sale 20:

https://backpack.tf/profiles/76561198361641167#!/compare/1541203200/1541980800

https://backpack.tf/profiles/76561198068191630#!/compare/1545436800/1545782400

SCM

Sale 21:

https://backpack.tf/profiles/76561198068191630#!/compare/1546646400/1546732800

https://backpack.tf/profiles/76561198019257028#!/compare/1546646400/1546732800

Sold with FoD Burst for Orb Highway

Low.

Sale 22:

https://backpack.tf/profiles/76561198282372085#!/compare/1546387200/1546473600

Untrace

Sale 23:

https://backpack.tf/profiles/76561198282372085#!/compare/1546473600/1546560000

https://backpack.tf/profiles/76561198060728416#!/compare/1546300800/1546560000

Sold for DBD Nasty + ~6 keys in sweets

Use there.

Sale 24:

https://backpack.tf/profiles/76561198060728416#!/compare/1546560000/1546646400

https://backpack.tf/profiles/76561198021272428#!/compare/1546560000/1546646400

QS?

Sale 25:

https://backpack.tf/profiles/76561198021272428#!/compare/1547078400/1547164800

https://backpack.tf/profiles/76561198171409190#!/compare/1547078400/1547164800

Sold for ~22 keys

Sale 26:

https://backpack.tf/profiles/76561198080179568#!/compare/1540166400/154025280

https://backpack.tf/profiles/76561198085907945#!/compare/1539475200/154068480

Untrace

Sale 27:

https://backpack.tf/profiles/76561198255289372#!/compare/1540944000/1541030400

https://backpack.tf/profiles/76561198275783474#!/compare/1540857600/1540944000

Untrace

Sale 28:

https://backpack.tf/profiles/76561198275783474#!/compare/1541289600/1541635200

https://backpack.tf/profiles/76561198106940627#!/compare/1546819200/1546905600

Bulky QS

Sale 29:

https://backpack.tf/profiles/76561198159470037#!/compare/1541203200/1541635200

Sold for 19 keys

Sale 30:

https://backpack.tf/profiles/76561198148213857#!/compare/1541548800/1546560000

https://backpack.tf/profiles/76561198104326108#!/compare/1538352000/1541635200

Untrace

Sale 31:

https://backpack.tf/profiles/76561198104326108#!/compare/1538352000/1541635200

https://backpack.tf/profiles/76561198080179568#!/compare/1541548800/1541635200

QS

Sale 32:

https://backpack.tf/profiles/76561198080179568#!/compare/1541635200/1541721600

https://backpack.tf/profiles/76561198333604071#!/compare/1541635200/1541721600

Sold for 20 keys

Sale 33:

https://backpack.tf/profiles/76561198333604071#!/compare/1541808000/1541894400

https://backpack.tf/profiles/76561198142892266#!/compare/1541808000/1541894400

Untrace

Sale 34:

https://backpack.tf/profiles/76561198119149660#!/compare/1542067200/1542153600

https://backpack.tf/profiles/76561198295698596#!/compare/1533427200/1542067200

Untrace

Sale 35:

https://backpack.tf/profiles/76561198295698596#!/compare/1547510400/1547596800

https://backpack.tf/profiles/76561198055847835#!/compare/1547596800/1547683200

QS?

Sale 36 - 47:

https://marketplace.tf/items/30810;5;u107

Sold for 44.99, 44.59, 39, 44.99, 45, 44.44, 38.48, 29.01, 42.99, 29.05, 47.8, 49.99 USD

Keys at 1.78, 1.78, 1.78, 1.76, 1.75, 1.73, 1.70, 1.80, 1.76, 1.76, 1.75, 1.75 USD

Totals are 25.28, 25.05, 21.91, 25.56, 25.71, 25.69, 22.64, 16.12, 24.43, 16.51, 27.31, 28.57 Keys

Total sales @:

16.12, 16.51, 19, 20, 20, 21.91, 22,22, 22.64, 24.43, 25, 25.05, 25.28, 25.56, 25.69, 25.71, 27.31, 28.57 keys

Buyers up to 19 keys, only one though. including.

Sellers down to 24,

Buyers up to 19 keys,

Polar's Part:

I think it's unfair to include 19 in the range (quickbuyer at 19 and others at 18+) and not include all the sales over 23. I would personally favor 19-25 but my guess is that other people would advocate for 20-23. I think either can work.

With 23 having sold for 19,

calling 19 low,

Taking 20 - 24 keys.