Resuggesting, thank you Xergoyf.

Sales

Sale 1: Untrace

https://backpack.tf/profiles/76561198253177889#!/compare/1598832000/1598918400

https://backpack.tf/profiles/76561198309832044#!/compare/1598227200/1599523200

Sale 2: Traced 10 keys + 25 refined

https://backpack.tf/profiles/76561198155371354#!/compare/1597104000/1598054400

https://backpack.tf/profiles/76561198363395191#!/compare/1597881600/1597968000

Buyorder was 13~ so probably 13 here.

https://bot.tf/stats/listings/MGLNW51W

Sale 3: Backpack buy/bulk

https://backpack.tf/profiles/76561198261509772#!/compare/1597795200/1599868800

https://backpack.tf/profiles/76561197994697258#!/compare/1597708800/1598054400

Maybe backpack buy or bulky trade.

Sale 4: Untrace

https://backpack.tf/profiles/76561198170385863#!/compare/1594425600/1596240000

https://backpack.tf/profiles/76561198261509772#!/compare/1594166400/1597536000

Exchanges with marketplace

https://backpack.tf/item/8580443420

https://backpack.tf/item/8856042502

Marketplace

https://marketplace.tf/items/tf2/31098;5;u145

June

$29 on June 15 (29/1.99 = 15~)

https://manic.tf/keyprice/?at=2020-06-15

44.44 on June 22 (44.44/1.98 = 22~)

https://manic.tf/keyprice/?at=2020-06-22

July

$39.95 on July 15 (39.95/1.99 = 20~)

https://manic.tf/keyprice/?at=2020-07-15

August

$34.95 on August 1 (34.95/1.91 = 18~)

https://manic.tf/keyprice/?at=2020-08-01

Listings during the time: https://bot.tf/stats/listings/MQ060X03

September

$24.5 on September 8 (24.5/1.83 = 13~)

https://marketplace.tf/items/tf2/5021;6

https://manic.tf/keyprice/?at=2020-09-08

Listings during the time: https://bot.tf/stats/listings/Y3WXVEQ1

Buyers during the time show that 13 is low.

Classifieds

https://gyazo.com/1bba871babefb0d9101536fc3f003562

MPTF Classifieds

https://imgur.com/a/queKcia

3 mp sellers at $32, one at $33

Summary

Sales at 13 (likely).

Marketplace sales at 13, 15, 18, 20, and 22.

Conclusion

Buyers up to 14.8, going to exclude 13 here.

There is a seller at 17, but it is unbumped.

15 may be low (close to buyers), but two sales at lower to support 15 being included.

Due to multiple sellers at $32 on MPTF, 20 and 22 look high, going to exclude both.

Going with 15-18 here.