Interesting.

SALES

Untrace

https://backpack.tf/profiles/76561198026129220#!/compare/1589500800/1589587200

https://backpack.tf/profiles/76561198217101891#!/compare/1593129600/1593475200

Untrace

https://backpack.tf/profiles/76561198158198098#!/compare/1591488000/1594512000

https://backpack.tf/profiles/76561198382267048#!/compare/1591315200/1591747200

MARKETPLACE

https://marketplace.tf/items/tf2/1183;5;u3036

20 on may 13 (20/1.9 = 10.53 rounds to 11)

https://manic.tf/keyprice/?at=2020-05-13

39.5 on may 18 (39.5/1.89 = 20.9 rounds to 21)

https://manic.tf/keyprice/?at=2020-05-18

https://backpack.tf/item/8379872643

39.99 on may 27 (39.99/1.92 = 20.83 rounds to 21)

https://manic.tf/keyprice/?at=2020-05-27

20 on july 12 (20/1.98 = 10.1 rounds to 10)

https://manic.tf/keyprice/?at=2020-07-12

34.6 on july 22 (34.6/1.94 = 17.83 rounds to 18)

https://manic.tf/keyprice/?at=2020-07-22

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

Buyout of 16:

https://bot.tf/stats/listings/4O9251XQ > https://bot.tf/stats/listings/MGLO5ZXZ

CLASSIFIEDS

https://gyazo.com/724339dae544598b66495b684f951630

Buyers range from 6 to 9.

SUMMARY

1 @ 10 keys

1 @ 11 keys

1 @ 16 keys

2 @ 21 keys

CONCLUSION

Tough to say here to be honest. 21 seems like a high outlier due to the sales at far lower. 10 is close to the nearest buyer at 9. Going to exclude the highest and lowest sales here.

Taking 11-16 here.