Sale 1:

Sold for 11 keys (ID’s match)

http://www.tf2outpost.com/trade/28973479 - B/O of 11

Seller: https://backpack.tf/profiles/76561198050933686#!/compare/1496707200/1496793600

Buyer: https://backpack.tf/profiles/76561198136472723#!/compare/1496361600/1496793600

X = 11

Sale 2:

Sold for 11 keys

http://www.tf2outpost.com/trade/29236133 - B/O of 11, buyer comments here

Seller: https://backpack.tf/profiles/76561198136472723#!/compare/1497830400/1498348800

Buyer: https://backpack.tf/profiles/76561198173155142#!/compare/1498348800/1498780800

X = 11

Sale 3:

Sold for 10 keys

http://webcache.googleusercontent.com/search?q=cache:qUIoOHldwrkJ:www.tf2outpost.com/trade/29217371+&cd=1&hl=en&ct=clnk&gl=au – B/O of 10

Seller: https://backpack.tf/profiles/76561198035312409#!/compare/1496793600/1497139200

Buyer: https://backpack.tf/profiles/76561198238626850#!/compare/1497052800/1497139200

X = 10

Sale 4:

Sold for Aces High Mongolian (10)

No outpost

Seller: https://backpack.tf/profiles/76561198141168144#!/compare/1495152000/1495238400

Buyer: https://backpack.tf/profiles/76561198163336781#!/compare/1495152000/1495238400

X = 10

Sale 5:

Sold for 9 keys + <0.5 keys in metal (Buyer’s compare link)

Seller: https://backpack.tf/profiles/76561198304138933#!/compare/1496188800/1496275200

Buyer: https://backpack.tf/profiles/76561198155872356#!/compare/1496188800/1497225600

X = 9

Sale 6:

Sold for 9 keys + 2 ref

No outpost

Seller: https://backpack.tf/profiles/76561198211529791#!/compare/1500336000/1500422400

Buyer: https://backpack.tf/profiles/76561198105403535#!/compare/1500336000/1500422400

X = 9

Sale 7:

Bulk for Logo Napper’s

Seller: https://backpack.tf/profiles/76561198294341247#!/compare/1495756800/1496016000

Buyer: https://backpack.tf/profiles/76561198106771968#!/compare/1495929600/1496016000

Sale 8:

Sold for Bubbling Swagman’s

No outpost

Seller: https://backpack.tf/profiles/76561198006356263#!/compare/1495152000/1495584000

Buyer: https://backpack.tf/profiles/76561198141168144#!/compare/1495065600/1495152000

Probably better suited on the Swagman’s, due to lack of B/O here.

Sale 9:

Sold with items for Kill-a-Watt Pampered Pyro

Seller: https://backpack.tf/profiles/76561198163336781#!/compare/1496275200/1496361600

Buyer: https://backpack.tf/profiles/76561198035312409#!/compare/1495929600/1496361600

Being used on the Pampered Pyro.

Sellers:

10 keys:

http://i.imgur.com/CRq9ThH.png - 7 days

13 keys:

http://i.imgur.com/FftFXSS.png

Sales at:

9 (2x)

10 (2x)

11 (2x)

Buyer at 9+ keys:

http://i.imgur.com/zwv7zwS.png

Excluding 9.

Going with 10-11.