Sales supporting the price:

Sale 1:

Sold for 34 keys

http://www.tf2outpost.com/trade/27839436 - B/O of 34

http://backpack.tf/profiles/76561198006544512/#!/compare/1455609600/1455696000

http://backpack.tf/profiles/76561198150774204/#!/compare/1455609600/1456300800

X = 34

Sale 2:

Sold for Cloud 9 Burning Bandana

http://www.tf2outpost.com/trade/27766899 - B/O of 40

Seller: http://backpack.tf/profiles/76561198155927905/#!/compare/1453881600/1453968000

Buyer: http://backpack.tf/profiles/76561198161072716/#!/compare/1451808000/1453968000

X = 32.5

Rounding to 33

Sale 3:

Sold for Circling Peace Sign Bubble Pipe

No outpost link available

Seller: http://backpack.tf/profiles/76561198071601053/#!/compare/1453708800/1453881600

Buyer: http://backpack.tf/profiles/76561198155927905/#!/compare/1453622400/1453881600

Bubble Pipe: http://backpack.tf/item/4067244384 (Blindfold --> Plague Doctor)

There may have been a trade hold

X = 21

Sale 3:

Quicksold for 25 keys?

http://www.tf2outpost.com/trade/27829987

Seller: http://backpack.tf/profiles/76561198055114799/#!/compare/1455091200/1455350400

Buyer: http://backpack.tf/profiles/76561198006544512/#!/compare/1455004800/1455091200

X = 25

Additional Sales:

Sale 5:

Sold (in ~1 day) with Kill-a-Watt Outdoorsman for Pro. KS Australium Grenade Launcher

http://www.tf2outpost.com/trade/27770727 - B/O of Pro. KS Australium Grenade launcher

Seller: http://backpack.tf/profiles/76561198161072716/#!/compare/1453968000/1454054400

Buyer: http://backpack.tf/profiles/76561198090956917/#!/compare/1453968000/1454054400

Sellers:

35 keys:

http://puu.sh/nrMvq/3d7332ea5e.png - 1 month

36 keys:

http://www.tf2outpost.com/trade/26998126 - 5 months

40 keys:

http://www.tf2outpost.com/trade/27903477 - 1 week, duped, offer of 30

Buyers:

22 keys

http://www.tf2outpost.com/trade/26826498

http://www.tf2outpost.com/trade/26827654

http://www.tf2outpost.com/trade/26758661

http://www.tf2outpost.com/trade/27173068

http://www.tf2outpost.com/trade/26389536

http://www.tf2outpost.com/trade/27897287

23 keys:

http://www.tf2outpost.com/trade/27611264

http://www.tf2outpost.com/trade/27808654

http://www.tf2outpost.com/trade/27667754

Sales at:

21 (Countered by buyers at higher)

25 (Quicksale)

33

34

Going with 33-34