MP sales:

https://marketplace.tf/items/tf2/30618;5;u3008

Feb 6: 7.5 / 1.75 = 4.25

Feb 9: 7.5 / 1.78 = 4.2

Feb 13: 7.5 / 1.75 = 4.25 https://backpack.tf/item/5539726741

Bot.tf sales:

https://bot.tf/stats/item?def=30618&q=5&ef=Midnight+Whirlwind&craft=1&aus=0&ks=0

1 @ 3 keys, 16.00 ref 20/01/2020

1 @ 3 keys, 16.00 ref 23/01/2020

1 @ 3 keys, 12.00 ref 13/02/2020

1 @ 3 keys, 15.88 ref 29/02/2020

Rounding to 3.25 keys

Other trades:

1. https://backpack.tf/item/6496071304

https://backpack.tf/profiles/76561198064458811#!/compare/1579219200/1580860800

2. https://backpack.tf/item/6208766135

https://backpack.tf/profiles/76561198139418570#!/compare/1582675200/1585612800

Sold for 2 keys 3 ref. Lower than buy orders.

3. https://backpack.tf/item/4422799992

https://backpack.tf/profiles/76561198168863803#!/compare/1583020800/1583107200

Sold for 3 keys.

4. https://backpack.tf/item/4422799992

https://backpack.tf/profiles/76561198354656940#!/compare/1583107200/1583193600

Unusable

Taking 3 - 4.25 keys.