Sale 1:

Sold for 10 keys

http://www.tf2outpost.com/trade/27690037 - B/O of 11, lowered to 10 was relisted multiple times

Seller: http://backpack.tf/profiles/76561198089596443/#!/compare/1458111600/1458543600

Cannot find buyer’s backpack

X = 10

Sale 2:

Sold with Strange Pro. KS Widowmaker for Spec. KS Australium Force a Nature

http://www.tf2outpost.com/trade/27936736 - B/O of 11

Seller: http://backpack.tf/profiles/76561198116752819/#!/compare/1457510400/1457596800

Buyer: http://backpack.tf/profiles/76561198200721065/#!/compare/1457510400/1457596800

X + 4 = 14

X = 10

Sale 3:

Sold with ~3 keys in items for Aces High Scotch Bonnet

Seller: http://backpack.tf/profiles/76561198159375235/#!/compare/1459728000/1459900800

Buyer: http://backpack.tf/profiles/76561198172573626/#!/compare/1459641600/1459900800

X + 3 = 13

X = 10

Sale 4:

Quicksold for 10 keys

http://www.tf2outpost.com/trade/28027108 - B/O of 10

Seller: http://backpack.tf/profiles/76561198009272632/#!/compare/1459382400/1459468800

Buyer: http://backpack.tf/profiles/76561198083673352/#!/compare/1459382400/1459468800

X = 10

Sale 5:

Sold for Strange Pro. KS Wrench

No outpost link

Seller: http://backpack.tf/profiles/76561198198912586/#!/compare/1456560000/1456819200

Buyer: http://backpack.tf/profiles/76561198116752819/#!/compare/1456732800/1456819200

X = 9

Sale 6:

Sold for Nuts n Bolts German Gonzila + 1 key

No outpost link

Seller: http://backpack.tf/profiles/76561198155108220/#!/compare/1458198000/1458284400

Buyer: http://backpack.tf/profiles/76561198046812473/#!/compare/1457938800/1458284400

X = 10.5 + 1

X = 12

Sale 7:

Sold for ~10 keys in painted junk

No outpost link

Seller: http://backpack.tf/profiles/76561198200721065/#!/compare/1457856000/1457938800

Buyer: http://backpack.tf/profiles/76561198102705999/#!/compare/1457856000/1458025200

Sale 8:

Sold for Steaming Sola Topi

Seller: http://backpack.tf/profiles/76561198083673352/#!/compare/1459382400/1459468800

Buyer: http://backpack.tf/profiles/76561198175500641/#!/compare/1459382400/1459468800

Would rather have this sale update the Topi

Sellers:

11 keys:

http://puu.sh/otfLQ/b972a29907.png - young-ish

Offers:

http://www.tf2outpost.com/trade/28083753 - 6 days

Buyer at 9 keys:

http://www.tf2outpost.com/trade/28100462

Sales at:

9

10

10

10

10

12

Sale at 9 is countered by buyer

Would normally exclude 12 in this situation, but a few of the 10 key sales happened pretty quickly.

Going with 10-12