History 1: https://backpack.tf/item/9330113781

Sold on Marketplace.tf February 14

History 2: https://backpack.tf/item/7245025121

Sold for 25 keys:

https://backpack.tf/profiles/76561198325595749#!/compare/1611878400/1611964800

https://backpack.tf/profiles/76561198171861038#!/compare/1611878400/1612051200

Marketplace.tf: https://marketplace.tf/items/tf2/30918;5;u3038

February 14: $89.99/2.12=42.45 ~42 keys

March 11: $69.99/2.19=31.96 ~32 keys

Unsolds:

35 keys for 2 months: https://backpack.tf/item/9406143205

Mannco.Store at ~37 keys (70/1.91=36.65 keys) https://mannco.store/item/27538

Two on Marketplace.tf at ~42 keys (89.99/2.15=41.86 keys) https://marketplace.tf/items/tf2/30918;5;u3038

Sales at 25, 32, 42

Given the unsold at 35 for 2 months and the other unsold at 36, 42 looks like a high outlier here

Going with 25-32