77 exist, not bad

sales

sold for 9 keys + 7 ref (rounds to 9)

https://backpack.tf/profiles/76561198045944174#!/compare/1592352000/1592784000

https://backpack.tf/profiles/76561198341171690#!/compare/1592265600/1592352000

buyorder

https://bot.tf/stats/listings/Y3W1VXLR

sold for 9 keys

https://backpack.tf/profiles/76561198841279602#!/compare/1589500800/1589587200

https://backpack.tf/profiles/76561198044719739#!/compare/1589328000/1589587200

2 exchanges with scrap

https://backpack.tf/item/7584830029

upgraded for aussie scatter

https://backpack.tf/profiles/76561198092578541#!/compare/1589155200/1589241600

https://backpack.tf/profiles/76561198148511293#!/compare/1589068800/1589155200

untrace

https://backpack.tf/profiles/76561198134220286#!/compare/1591920000/1592006400

https://backpack.tf/profiles/76561198363395191#!/compare/1591833600/1591920000

untrace

https://backpack.tf/profiles/76561198014250683#!/compare/1593043200/1594166400

https://backpack.tf/profiles/76561198061108999#!/compare/1592956800/1593043200

marketplace

https://marketplace.tf/items/tf2/31010;5;u120

19.95 on may 19 (19.95/1.89 = 11 keys~)

https://manic.tf/keyprice/?at=2020-05-19

https://backpack.tf/item/7320587855

21.11 on may 27 (21.11/1.92 = 11 keys~)

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

21.11 on may 31 (21.11/1.91 = 11 keys~)

https://manic.tf/keyprice/?at=2020-05-31

25 on june 2 (25/1.94 = 13 keys~)

https://manic.tf/keyprice/?at=2020-06-02

19 on june 10 (19/2.01 = 9.5 keys~)

https://manic.tf/keyprice/?at=2020-06-10

21 on july 5 (21/1.99 = 11 keys~)

https://manic.tf/keyprice/?at=2020-07-05

assuming this one https://backpack.tf/item/7271671134

21 on july 10 (21/1.95 = 11 keys~)

https://manic.tf/keyprice/?at=2020-07-21

21.67 on july 25 (21.67/1.93 = 11 keys~)

https://manic.tf/keyprice/?at=2020-07-25

classifieds

https://gyazo.com/c109a13e162e727eb365f3ebf67435d2

3x sellers @ 10 keys

summary

2 @ 9 keys

1 @ 9.5 keys

6 @ 11 keys

1 @ 13 keys

conclusion

there are 3 sellers at 10, but also 6 sales at 11, seems common enough to include.

going to exclude 13 as it's a bit higher.

one 9 was sold to buyorder, but seems common to include, as 9.5 also supports it.

taking 9-11 here.