Sale 1:

http://backpack.tf/profiles/76561198086659946#!/compare/1465344000/1465689600 ~22 Keys

~Sold for 22 Keys pure

Sale 2:

http://backpack.tf/profiles/76561198078298306#!/compare/1465344000/1465430400 ~15 Keys

~Sold for 17 Keys Pure with 36 Ref (1.8 Keys)

17-1.8= 15 Keys

Sale 3:

http://backpack.tf/profiles/76561198253383258#!/compare/1465084800/1465171200

~Sold for A Terror-Watt Tam O' Shanter + 2 Tinge Paints (Uncraftable)

15+1.4 = 16 Keys

Mini for Shanter:

http://backpack.tf/profiles/76561198243557436#!/compare/1462924800/1463011200 ~15 Keys

~Sold with 19 Keys in items for Terror-Watt Nickel Amassment with 1 Key in items

34-19 = 15 Keys

Sale 4:

http://backpack.tf/profiles/76561198058423925#!/compare/1464998400/1465257600

~Sold with 1 Key in items for a Haunted Ghosts Handyman's and 4 Keys in items

(18.5+4)-1= 21 Keys

Buyer at 17:

http://www.tf2outpost.com/trade/27759748

Credits to Jarool

Making a range here 21-22 Keys

Any proof or counter is appreciated, Thank you.