This needs a slight bump down. Although there is a seller at 0.66 ref, it's only one, and there is one buyer at 0.77 ref

Proof:

Buyers:

TONS of people buying for 0.66 ref

Buying for 0.77 ref:

http://www.tf2outpost.com/trade/9005263

Offered 1 ref for Kills while explosive jumping http://www.tf2outpost.com/trade/8668913

Sellers:

Selling for 0.66 ref:

http://www.tf2outpost.com/trade/9107332

Selling for 0.88 ref:

http://www.tf2outpost.com/trade/6570642

Unsold for 1 ref:

Last add 1 month ago http://www.tf2outpost.com/trade/6935841

Last add 3 weeks ago http://www.tf2outpost.com/trade/7890783

2 weeks, no adds http://www.tf2outpost.com/trade/8760294

2 weeks, no adds http://www.tf2outpost.com/trade/8721462

Last add, 1 week ago http://www.tf2outpost.com/trade/8299812

1 week http://www.tf2outpost.com/trade/8966871

1 week, no adds http://www.tf2outpost.com/trade/8983846

5 days http://www.tf2outpost.com/trade/9025918

5 days http://www.tf2outpost.com/trade/9031531

5 days http://www.tf2outpost.com/trade/9038809

4 days http://www.tf2outpost.com/trade/9062089

3 days http://www.tf2outpost.com/trade/9072099

2 days http://www.tf2outpost.com/trade/9089293

2 days http://www.tf2outpost.com/trade/9100199

1 day http://www.tf2outpost.com/trade/9110697

1 day http://www.tf2outpost.com/trade/9113578

1 day http://www.tf2outpost.com/trade/9121678

18 hrs http://www.tf2outpost.com/trade/9134282

3 hrs http://www.tf2outpost.com/trade/9151504

Classifieds at 1 ref: one for 4 dayshttp://backpack.tf/classifieds/search/205/11/0