thanks blaze

sale 1: sold for 19 keys

https://backpack.tf/profiles/76561198823736236#!/compare/1554163200/1554422400

sale 2: 3 sales on marketplace from may 8, may 9, and may 16 (all for 2019)

https://marketplace.tf/items/30682;5;u102

26.71 USD / 1.8 = 14.8 rounding to 15

32.24 USD / 1.8 = 17.9 rounding to 18

28 USD / 1.82 = 15.3 rounding to 15

sale 3: sold for 20 keys

https://backpack.tf/profiles/76561198021055079#!/compare/1557964800/1558051200

https://backpack.tf/profiles/76561198161653465#!/compare/1557878400/1558051200

(credits to blaze for this sale)

buyers at 15

https://gyazo.com/7829ab8c92e7a33f487e27d6089e8f02

i have sales at 15, 15, 18, 19 and 20. with multiple buyers at 15, 15 is low, making a range of 18 - 20 keys.