There's a seller for the regular version at 80 right now and its been there for 7 months so I'm pretty sure anything above that is too high, and if you are going to be including the strange versions then you'd have to look at these for any other sales

https://backpack.tf/item/13003885758

https://backpack.tf/item/2506015459

https://backpack.tf/profiles/76561199026390261#!/compare/1690329600/1690416000 - ?

https://backpack.tf/profiles/76561198188093413#!/compare/1688515200/1688601600 - ?

https://backpack.tf/profiles/76561198332033797#!/compare/1692144000/1696550400 - ?

https://backpack.tf/profiles/76561198245904110#!/compare/1687219200/1687305600 - Better for the Classy Capper

https://backpack.tf/profiles/76561197998883721#!/compare/1692316800/1692403200 - ?

https://backpack.tf/profiles/76561197998883721#!/compare/1692403200/1692662400 - ?

https://backpack.tf/profiles/76561198084635414#!/compare/1694044800/1694217600 - Bulk sale

Up until a month ago, one hadn't sold for 80 Keys since February.

https://gladiator.tf/time-machine?item=Cloud+9+Anger&at=2023-09-03T23%3A47%3A00.000Z

There's a current seller at 80 Keys who's had theirs listed for a month so far.

https://gladiator.tf/time-machine?item=Strange+Cloud+9+Anger&at=2023-10-08T22%3A50%3A00.000Z

As such, the sales at 84 and 85 will be too high to use here. 75 as a rounded flat value would work better here.