6 months here.

Sold for 27 keys

https://backpack.tf/profiles/76561198156255538#!/compare/1588377600/1588464000

https://backpack.tf/profiles/76561198070983297#!/compare/1588291200/1588464000

Unknown

https://backpack.tf/profiles/76561198069302272#!/compare/1588204800/1588377600

https://backpack.tf/profiles/76561198156255538#!/compare/1588118400/1588204800

Sold with 3 other hats for 53 keys

https://backpack.tf/profiles/76561198183424550#!/compare/1586563200/1586995200

https://backpack.tf/profiles/76561198069302272#!/compare/1586476800/1586822400

Sold for 50 on March 27, 2020

50/1.69 = 29.58 rounding to 30 keys

https://marketplace.tf/items/tf2/248;5;u37

https://backpack.tf/item/1222604703

No buyout found.

Sold for 33.33 on May 2, 2020

33.33/1.87 = 17.82 rounding to 18 keys

https://marketplace.tf/items/tf2/248;5;u37

No buyout found.

Classifieds:

https://gyazo.com/7de25ee9506318c564c98d7b5c1c9877

Sales are at 18, 27, and 30. Buyers are at 17+. 18 is quite close, and seems low here. Excluding 18.

Taking a range of 27-30 keys here.