Resuggest, I don't think cleverpun's counter-proof are good enough to close my suggestion.

Sold for 1.66

http://www.tf2outpost.com/trade/21034731

http://www.tf2outpost.com/trade/21027891 (Traded for a Tough Guy's Toque = 1.66)

http://imgur.com/xzTAPaX

Sellers (provided by cleverpun)

http://www.tf2outpost.com/trade/20971993 - 1.55 (In my range)

http://www.tf2outpost.com/trade/21015500 - 1.66 (have an add)

http://www.tf2outpost.com/trade/21019970 - 1.66

http://www.tf2outpost.com/trade/21064202 - 1.22 (Sold less than 1 day)

http://www.tf2outpost.com/trade/21064098 - 1.33 (Sold less than 1 day, in the range)

http://www.tf2outpost.com/trade/21026632 - 1.33 (Sold)

http://www.tf2outpost.com/trade/21066130 - 1.33 (Sold less than 1 day)

http://www.tf2outpost.com/trade/21036436 - 1.33 (Poorly bump)

Conclusion: 1.66 is possible, along with 1.33. The range I make is fine as both 1.33 and 1.66 can happen.

Feel free to counter / support my proofs.

Forgot to say this: 1.66 happened enough not to be classified as "Outlier".