Taking last 2 months.

Sale 1:

https://backpack.tf/profiles/76561198335791307#!/compare/1564704000/1564790400

https://backpack.tf/profiles/76561198062353074#!/compare/1564099200/1564790400

Keys

Sale 2:

https://backpack.tf/profiles/76561198046277176#!/compare/1564099200/1565222400

https://backpack.tf/profiles/76561198303229300#!/compare/1564099200/1565308800

SCM

Sale 3:

https://backpack.tf/profiles/76561198860234199#!/compare/1564963200/1564963200

https://backpack.tf/profiles/76561198340634356#!/compare/1567814400/1567900800

Untrace

Sale 4:

https://backpack.tf/profiles/76561198845896241#!/compare/1567814400/1567900800

https://backpack.tf/profiles/76561198391225580#!/compare/1567814400/1567987200

SCM

Sale 5:

https://backpack.tf/profiles/76561198391225580#!/compare/1568332800/1568505600

https://backpack.tf/profiles/76561198334598690#!/compare/1568419200/1568505600

Sold for ~3.1 keys

Sale 6:

https://backpack.tf/profiles/76561198841279602#!/compare/1564272000/1564358400

https://backpack.tf/profiles/76561198124070734#!/compare/1563148800/1567123200

Untrace

Sale 7:

https://backpack.tf/profiles/76561198196644661#!/compare/1567814400/1568332800

https://backpack.tf/profiles/76561198384369082#!/compare/1568246400/1568332800

Untrace

Sale 8:

https://backpack.tf/profiles/76561198384369082#!/compare/1568332800/1568419200

https://backpack.tf/profiles/76561198320615503#!/compare/1568332800/1568419200

Untrace

Sale 9:

https://backpack.tf/profiles/76561198058945858#!/compare/1566345600/1568851200

https://backpack.tf/profiles/76561198101300189#!/compare/1566604800/1566691200

https://backpack.tf/profiles/76561198880237311#!/compare/1566518400/1566691200

Untrace

Sale 10:

https://backpack.tf/profiles/76561198340634356#!/compare/1564099200/1564185600

https://backpack.tf/profiles/76561198058533195#!/compare/1562976000/1565568000

Keys

Sale 11:

https://backpack.tf/profiles/76561198382654640#!/compare/1565827200/1565913600

https://backpack.tf/profiles/76561198439634067#!/compare/1557964800/1567814400

Sod with ~0.6 keys in sweets for 4 keys

Total is ~3.4 keys

Sale 12:

https://backpack.tf/profiles/76561198166763414#!/compare/1567641600/1567900800

https://backpack.tf/profiles/76561198340634356#!/compare/1567555200/1567641600

Sold for ~3.1 keys

Sale 13:

https://backpack.tf/profiles/76561197960452327#!/compare/1568073600/1568160000

https://backpack.tf/profiles/76561198841279602#!/compare/1568073600/1568160000

Sold for ~3.05 keys

Sale 14 - 19:

https://marketplace.tf/items/tf2/30671;5;u3009

$6.07 / $1.80 = 3.37 keys

$6.5 / $1.80 = 3.61 keys <-- https://backpack.tf/item/6380641358

$6.5 / $1.82 = 3.57 keys <-- https://backpack.tf/item/4670760188

$6.5 / $1.82 = 3.57 keys

$6.5 / $1.83 = 3.55 keys

$7 / $1.82 = 3.85 keys

Bot.tf:

https://bot.tf/stats/item?def=30671&q=5&ef=Silver%20Cyclone&craft=1&aus=0&ks=0&source=browser_script

2 sales @ 3 keys,

1 sale @ 3.05 keys,

3 sales @ 3.10 keys,

1 sale @ 3.25 keys,

1 sale @ 3.45 keys

Total sales @:

3 (x2)

3.05 (x2)

3.1 (x5)

3.25

3.35

3.4

3.45

3.55 (x3)

3.6

3.85

Buyers up to ~2.9 keys,

Sellers down to 3.45 keys,

taking 3 - 3.45 keys