Sale 1: - Credit to Xergoyf

Sold for 22 keys

http://www.tf2outpost.com/trade/28509625 - B/O of 25

Seller: http://backpack.tf/profiles/76561198156255538#!/compare/1475193600/1475280000

Buyer: http://backpack.tf/profiles/76561198084976847#!/compare/1475020800/1475280000

http://imgur.com/a/OdIrc

http://imgur.com/a/W0fTk

X = 22

Sale 2:

Sold with 2 keys in items for Max’s Head (23 at the time)

No outpost

Seller: http://backpack.tf/profiles/76561198153510689#!/compare/1474588800/1474675200

Buyer: http://backpack.tf/profiles/76561198120382814#!/compare/1474675200/1474761600

X = 21

Sale 3:

Sold for Miami Nights Snaggle (17) + 4 keys

Seller: http://backpack.tf/profiles/76561198120382814#!/compare/1474675200/1474761600

Buyer: http://backpack.tf/profiles/76561198046941961#!/compare/1474761600/1474848000

X = 21

Sale 4:

Sold for 20 keys

http://www.tf2outpost.com/trade/28466644 - B/O of 20

Seller: http://backpack.tf/profiles/76561198055088168#!/compare/1473379200/1473465600

Buyer: http://backpack.tf/profiles/76561198068825704#!/compare/1473379200/1473465600

X = 20

Sale 5:

Sold for Miami Nights Bunsen Brave

No outpost

Seller: http://backpack.tf/profiles/76561198138660659#!/compare/1472947200/1473033600

Buyer: http://backpack.tf/profiles/76561198055088168#!/compare/1472860800/1472947200

X = 20

Sale 7:

Sold with Strange Festive Huntsman (5) + minor items for Max’s (23 at the time) + ~1.5 keys in items

http://www.tf2outpost.com/trade/28389782 - No B/O

Seller: http://backpack.tf/profiles/76561198103463234#!/compare/1476576000/1477785600

Buyer: http://backpack.tf/profiles/76561198069527288#!/compare/1477267200/1477353600

X = 19

Sale 8:

Sold for Smoking Pampered Pyro + Strange Spec. KS Festive Stickybomb Launcher (6) + Strange Gold Botkiller Scattergun MK.I (3) + ~4 keys in items

http://www.tf2outpost.com/trade/28564343 - No B/O

Seller: http://backpack.tf/profiles/76561198069527288#!/compare/1477699200/1477785600

Buyer: http://backpack.tf/profiles/76561198035535731#!/compare/1477785600/1477958400

Without a B/O to cap at, this sale would be an outlier.

Sellers:

600 ref: (24.75 keys)

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

http://backpack.tf/u/76561198071307854

http://www.tf2outpost.com/trade/28602355

Offers:

http://www.tf2outpost.com/trade/28578553

http://backpack.tf/u/76561198081321409

Sales at:

19

20 (2x)

21 (2x)

22

Going with 19-22