Thanks to Shuffle for the freebie and the previous suggestor Burn as I am borrowing proof from them

https://backpack.tf/suggestion/5f424dbd65a3ad749362bc70

Marketplace : https://marketplace.tf/items/tf2/445;5;u29

May 28: 29.99/1.91 = ~16 keys

No b/o found

https://backpack.tf/item/659230388 (?)

Jun 1: 39.99/1.92 = ~21 keys

No b/o found

Jun 23: 26.07/2 = 13.04 keys

Excluding, this sale is below mp buyers

Jul 10: 39.99/2 = 20 keys

https://backpack.tf/item/1706688002

https://bot.tf/stats/listings/4P06QG6E - b/o of 20

Sept 7: 65/1.83 = 35.52 keys

Sept 16: 37.99 / 1.85 = 20.54 keys

Sales

https://backpack.tf/profiles/76561198101398885#!/compare/1593993600/1594080000

https://backpack.tf/profiles/76561198260968131#!/compare/1593907200/1593993600

KaW noir + pfetti esteem

noir indate at 13, esteem indate at 6.5

13 + 6.5 = 19.5 rounding to 20 keys

No b/o

https://imgur.com/a/49E0Th9

17 keys

https://backpack.tf/profiles/76561198249078668#!/compare/1600041600/1600128000

- Sold for 18 Keys

https://backpack.tf/profiles/76561198125894529#!/compare/1600387200/1600473600

- Sold + ~1 Key of Items for a GE Hetman's

https://backpack.tf/profiles/76561198059474977#!/compare/1600473600/1600646400

- Sold for a Smoking Pith + Logo Bombing Run

https://backpack.tf/profiles/76561198059474977#!/compare/1600819200/1600905600

- Sold for 17 Keys

https://backpack.tf/profiles/76561198120443406#!/compare/1600992000/1601078400

- Sold for a PE Brain-Warming + ~1 Key of Items

https://backpack.tf/profiles/76561198174973402#!/compare/1600819200/1601251200

- Sold for a P. Fetti Murderer's Motif (use there)

https://backpack.tf/profiles/76561198195933333#!/compare/1601164800/1601251200

- Quicksold for 17 Keys + 9 Refined

Taking 18-20 as Shuffle said.