Lowering the range a bit. Very few on the market, doesn't look like these sell for 0.66 at all. These were all the relevant trades I could find:

SELLERS

http://www.tf2outpost.com/trade/9586933 0.66, unsold for 1 month

http://www.tf2outpost.com/trade/10365313 0.66, unsold for 1 week

http://www.tf2outpost.com/trade/10477724 wants 0.66 (check comments), unsold for 5 days, 2 offers of 0.33

http://www.tf2outpost.com/trade/10560464 Selling for 0.44

http://www.tf2outpost.com/trade/9444879 Sold for 0.33

BUYERS

http://www.tf2outpost.com/trade/9367603 Looking for a rec (check the comments), one person said they'll "think about it", someone also wanted to sell the b-ankh + a futankhamun for 0.66 (Meaning the b-ankh = 0.44)

http://www.tf2outpost.com/trade/9758947 0.22, no success

There are also 2 0.33 buyers, but they're both under a day old, so I left them out,