Needs a bit of a drop:

Proof:

Classies:

http://backpack.tf/classifieds/search/id/51fffbe4ba2536cd7f000002 (1 at 17 keys and 1 at 19 keys)

Selling

18 keys:

http://www.tf2outpost.com/trade/15240839 (<1 day)

http://www.tf2outpost.com/trade/15150843 (4 days)

http://www.tf2outpost.com/trade/15190811 (3 days)

http://www.tf2outpost.com/trade/15177393 (3 days, poorly bumped)

17 keys, 4 ref:

http://www.tf2outpost.com/trade/15235955 (Sapper's destroyed, <1 day)

http://www.tf2outpost.com/trade/15011159 (Sapper's destroyed, 1 week)

17 keys: (1 bud):

http://www.tf2outpost.com/trade/14940042 (1 week)

http://www.tf2outpost.com/trade/15241462 (<1 day)

http://www.tf2outpost.com/trade/14792355 (3 weeks)

http://www.tf2outpost.com/trade/15132154 (Has 2, 5 days)

http://www.tf2outpost.com/trade/15242676 (<1 day)

As you can see, many a seller at 17 keys. Should be added to the range.

Thanks for voting : )