Sale 1:

Sold for Smoking Merc’s Mohawk (58.5)

http://www.tf2outpost.com/trade/29219527 - B/O of 50

Seller: https://backpack.tf/profiles/76561198087172601#!/compare/1497052800/1497139200

Buyer: https://backpack.tf/profiles/76561198122872975#!/compare/1497052800/1497139200

X = 50 (Capped by B/O)

Sale 2:

Sold for Peace Sign Wraith Wrap (42)

http://www.tf2outpost.com/trade/29214531 - B/O of 40, alleged offer of 38 pure

Seller: https://backpack.tf/profiles/76561198107934426#!/compare/1496620800/1496707200

Buyer: https://backpack.tf/profiles/76561198087172601#!/compare/1496620800/1496707200

X = 40 (Capped by B/O)

Sale 3:

Sold with ~9 keys in items for Green Energy Furious Fukaamigasa (36)

No outpost

Seller: https://backpack.tf/profiles/76561198182323073#!/compare/1496448000/1496620800

Buyer: https://backpack.tf/profiles/76561198107934426#!/compare/1496534400/1496620800

X = 27

Sale 4:

Bulk for Tesla Coldsnap Cap

Seller: https://backpack.tf/profiles/76561197998374145#!/compare/1492214400/1492300800

Buyer: https://backpack.tf/profiles/76561198208062409#!/compare/1492214400/1492300800

Sale 5:

Bulk for Beams Vive La France

Seller: https://backpack.tf/profiles/76561198208062409#!/compare/1493942400/1494028800

Buyer: https://backpack.tf/profiles/76561198131994315#!/compare/1493856000/1494028800

Sellers:

55 keys:

http://i.imgur.com/X7H63mM.png - 8 days

https://backpack.tf/item/5664378070

65 keys:

http://i.imgur.com/JF2ihdL.png

https://backpack.tf/item/5760976133

Sales at:

27

40

50

27 seems low, with the alleged offer of 38 keys pure (and maybe the other offers). Excluding 27.

Going with 40-50.