I can drop this with the classified listing alone.

Unsolds at 2.7 keys

http://www.tf2outpost.com/trade/22790760 - Painted

http://www.tf2outpost.com/trade/22831953 - Painted

http://www.tf2outpost.com/trade/22373699 - Painted

http://www.tf2outpost.com/trade/22819880 - Painted

Sold for 2.5 keys

http://www.tf2outpost.com/trade/22790760

Unsolds at 2.5 keys

http://www.tf2outpost.com/trade/22825051 - Painted

http://www.tf2outpost.com/trade/22823893 - Painted

http://www.tf2outpost.com/trade/22831939 - Painted

http://www.tf2outpost.com/trade/22779756 - Painted

http://www.tf2outpost.com/trade/22829412

http://www.tf2outpost.com/trade/22826896

http://www.tf2outpost.com/trade/22728814

http://www.tf2outpost.com/trade/22830790 - Painted

http://www.tf2outpost.com/trade/22761827

http://www.tf2outpost.com/trade/22620224

http://www.tf2outpost.com/trade/22792965

http://www.tf2outpost.com/trade/22801303

http://www.tf2outpost.com/trade/22822820

http://www.tf2outpost.com/trade/22714746

http://www.tf2outpost.com/trade/22820978

Selling/ Sold for 2.3 keys

http://www.tf2outpost.com/trade/22819231

http://www.tf2outpost.com/trade/22795408

http://www.tf2outpost.com/trade/22748262

http://www.trade.tf/trade/482083459

http://www.trade.tf/trade/482087727

Selling/ Sold for 2.2 keys

http://www.tf2outpost.com/trade/22828314 - Have 3, sold 2 for 2.2 keys, sold 1 to a quick-buyers for 2 keys.

http://www.tf2outpost.com/trade/21729790

http://www.trade.tf/trade/482131650

Selling/ Sold for 2 keys

http://www.tf2outpost.com/trade/22831939

http://www.tf2outpost.com/trade/22800267

http://www.tf2outpost.com/trade/22818261

Conclusion: Impossible to sell above 2.5 keys. Not include 2-key in the range because it's easy to find quick-buyers that are willing to pay 2 keys for it.

Feel free to counter / support my proofs.