And there it shows..

Sales

Sale 1: Sold for 26 keys + Aces High Tundra Top (15 keys)

https://backpack.tf/profiles/76561198088639894#!/compare/1592697600/1596153600

https://backpack.tf/profiles/76561198065749444#!/compare/1596067200/1596153600

26 + 15 = 41 keys

Sale 2: Sold for 40 keys?

https://backpack.tf/profiles/76561198152451196#!/compare/1600473600/1600819200

https://backpack.tf/profiles/76561198206567572#!/compare/1600732800/1600819200

Histories dont match, but it makes sense..

Sale 3: Sold for Enchanted Taunt: Panzer Pants (24 keys) + DP Fruit Shoot (7.5 keys)+ 5 keys

https://backpack.tf/profiles/76561198136556581#!/compare/1599868800/1599955200

https://backpack.tf/profiles/76561198152451196#!/compare/1599609600/1599868800

24 + 7.5 + 5 = 36.5 rounding to 37 keys

DP Fruit Shoot: https://backpack.tf/suggestion/5f6c00311a70bc6f0f627a4c

Sale 4: Sold for GE Festive Tree (41 keys) + 2 keys + 30 refined

https://backpack.tf/profiles/76561198275222296#!/compare/1598486400/1599177600

https://backpack.tf/profiles/76561198136556581#!/compare/1598400000/1598486400

41 + 3 + 0.63 = 45 keys~

Marketplace

https://marketplace.tf/items/tf2/344;5;u9

Nothing recent.

Classifieds

https://gyazo.com/c9709e341fe99a7f2a7c6079594a9369

Summary

Sales at 37, 40 (highly likely), 41, and 45.

Conclusion

Going with 37-45 here.