Now then.

Sales

Sale 1: Sold for Searing Trilby (16 keys)

https://backpack.tf/profiles/76561198337734785#!/compare/1595894400/1596067200

https://backpack.tf/profiles/76561198274503484#!/compare/1590796800/1595980800

Trilby: https://backpack.tf/suggestion/5f4701ab32bdb41bd908be8d

Sale 2: Untrace

https://backpack.tf/profiles/76561198091049661#!/compare/1593993600/1596844800

https://backpack.tf/profiles/76561197993422884#!/compare/1593820800/1593993600

Sale 3: Sold for 20 keys

https://backpack.tf/profiles/76561198000646505#!/compare/1590710400/1591488000

https://backpack.tf/profiles/76561198338949704#!/compare/1590624000/1591056000

Sale 4: Untrace

https://backpack.tf/profiles/76561198098005577#!/compare/1591488000/1591660800

https://backpack.tf/profiles/76561198043936328#!/compare/1591401600/1591488000

Sale 5: Untrace

https://backpack.tf/profiles/76561198850274253#!/compare/1593648000/1593907200

https://backpack.tf/profiles/76561198403714801#!/compare/1574294400/1596758400

Sale 6: Untrace

https://backpack.tf/profiles/76561198066813088#!/compare/1590710400/1591747200

https://backpack.tf/profiles/76561198082465971#!/compare/1590624000/1590710400

Sale 7: Sold for 16 keys

https://backpack.tf/profiles/76561198112281935#!/compare/1597363200/1597449600

https://backpack.tf/profiles/76561198146588706#!/compare/1596931200/1597363200

Other exchanges, such as mptf, qs store/loot farm exchanges, and etc.

https://backpack.tf/item/8710072776

Marketplace

https://marketplace.tf/items/tf2/31091;5;u142

May

$44 on May 29 (44/1.94 = 23~)

https://manic.tf/keyprice/?at=2020-05-29

June

$44.01 on June 8 (44.01/1.98 = 22~)

https://manic.tf/keyprice/?at=2020-06-08

16.06 on June 9 (16.06/1.99 = 8~)

https://manic.tf/keyprice/?at=2020-06-09

July

$44.01 on July 14 (44.01/1.93 = 23~)

https://manic.tf/keyprice/?at=2020-07-14

32.5 on July 28 (32.5/1.92 = 17~)

https://manic.tf/keyprice/?at=2020-07-28

August

$32.5 on August 16 (32.5/1.79 = 18~)

https://manic.tf/keyprice/?at=2020-08-16

Classifieds

https://gyazo.com/b04f010d3a56301be8c329bbee0f9129

Sellers at 22/23.

Buyers up to 15 keys~.

Summary

Sales at 16, 16, and 20.

Marketplace sales at 8, 17, 18, 22, 23, and 23.

Conclusion

Buyers up to 15 keys~. Excluding 8.

Going with a wider range of 16-23 here.