Found 4 instances with non-empty history.

https://backpack.tf/item/11357567623

Transaction_0_intent_buy

https://backpack.tf/profiles/76561199111874743#!/compare/1655164800/1656633600

Transaction_0_intent_sell

https://backpack.tf/profiles/76561199072654974#!/compare/1655942400/1656028800

untrace

https://backpack.tf/item/9772330007

Transaction_0_intent_buy

Transaction_0_intent_sell

sold for 20

https://backpack.tf/profiles/76561198316253710#!/compare/1660780800/1661126400

Transaction_1_intent_buy

https://backpack.tf/profiles/76561198316253710#!/compare/1660694400/1660780800

Transaction_1_intent_sell

sold for Aces High Otolaryngologist's Mirror + Terror-Watt Slick Cut = 17 keys

Transaction_2_intent_buy

Transaction_2_intent_sell

https://backpack.tf/profiles/76561198931754287#!/compare/1660694400/1660780800

sold for Terror-Watt Stately Steel Toe = 7.5 keys

Transaction_3_intent_buy

https://backpack.tf/profiles/76561198931754287#!/compare/1651190400/1660521600

Transaction_3_intent_sell

https://backpack.tf/profiles/76561199084784906#!/compare/1660435200/1660521600

untrace

Transaction_4_intent_buy

Transaction_4_intent_sell

https://backpack.tf/profiles/76561199168751553#!/compare/1657411200/1663113600

untrace

Transaction_5_intent_buy

https://backpack.tf/profiles/76561199168751553#!/compare/1657065600/1657411200

Transaction_5_intent_sell

https://backpack.tf/profiles/76561198311498888#!/compare/1657065600/1657152000

untrace

Transaction_6_intent_buy

Transaction_6_intent_sell

https://backpack.tf/item/8690384650

Transaction_0_intent_buy

https://backpack.tf/profiles/76561199184100727#!/compare/1652918400/1657670400

Transaction_0_intent_sell

https://backpack.tf/profiles/76561198216433313#!/compare/1654473600/1663027200

transfer to mp bot

https://backpack.tf/item/8275701654

Transaction_0_intent_buy

https://backpack.tf/profiles/76561198875789508#!/compare/1653609600/1658188800

Transaction_0_intent_sell

https://backpack.tf/profiles/76561199111073161#!/compare/1657929600/1658016000

untrace

Transaction_1_intent_buy

Transaction_1_intent_sell

https://backpack.tf/profiles/76561198850274253#!/compare/1656806400/1656892800

untrace

Transaction_2_intent_buy

https://backpack.tf/profiles/76561198850274253#!/compare/1656115200/1656201600

Transaction_2_intent_sell

https://backpack.tf/profiles/76561198012349211#!/compare/1656201600/1658448000

bulk

marketplace sales:

29/1.83=15.8

30/1.95=15.4

Sales:

7.5,

15.8,

15.4,

17,

20,

Buyers now 10.2

Sellers now 18

I exclude 7.5 sale, round and take range 16-20