Redoing my suggesting as its seems like to fall more with adjust slightly end range..

There are enough people attempting (and failing) to sell at 5 keys, that I think its safe to say we can wipe "6" off the board

http://backpack.tf/classifieds/search/944/600/0 -3 sellers at 4 key no buyers..

http://www.tf2outpost.com/trade/8143948 - 4 keys asking price

http://www.tf2outpost.com/trade/6929302 - C/O Ebenezer (4 keys)

http://www.tf2outpost.com/trade/7755259 - 4 key 3 ref C/O

http://www.tf2outpost.com/trade/8101134 - 5 keys, no offers, 1 week old

http://www.tf2outpost.com/trade/7697035 - 5 keys, no firm offers. - 2 weeks old

http://www.tf2outpost.com/trade/8184001 - 5 keys, no offers

http://www.tf2outpost.com/trade/8158320 - 5 keys, no offers

http://www.tf2outpost.com/trade/8129387 - 5 key B/O, C/O of 6 refined (less than a key)

http://www.tf2outpost.com/trade/8020498 - 5 keys, no offers.

Conclusion - People Dont want this things anymore and people with b/o of 5 and Unsucces to sell and c/o of 4 key seems success...

http://backpack.tf/classifieds/search/944/600/0 -3 sellers at 4 key no buyers..

New proof and 4-4.5 keys seems more fine range at 5 people failing and at 4 people trying to sell