Proof:

Last Suggestion (Credit to KoDoRiN):

5 ref sales

http://www.tf2outpost.com/trade/18289804 | http://www.tf2outpost.com/trade/18273903

http://backpack.tf/classifieds/search/id/52c9bbe64cd7b8730b8b456a --> http://puu.sh/7eEcr.png

http://backpack.tf/classifieds/search/id/52cc26d04dd7b87f4b8b4567 --> http://puu.sh/7eEmp.png

http://backpack.tf/classifieds/search/id/52c9eaae4dd7b8ea778b4567 --> http://puu.sh/7eEnI.png

http://puu.sh/7eE5T.png

http://puu.sh/7eH6t.png

about 8 ref in items. (Credit to Wesley)

My Proof:

Sales at 5 ref:

http://imgur.com/QKOeKmD - 1 Sale

http://imgur.com/n3jMH8i - 2 Sales

http://www.tf2outpost.com/trade/18321526 - Less than 10 hours

http://www.tf2outpost.com/trade/18338224 - Less than 9 hours

http://www.tf2outpost.com/trade/18316574 - Less than 4 hours

http://www.tf2outpost.com/trade/18332629 - 1 key, less than a day

http://www.tf2outpost.com/trade/18339248 - 1 key, 1 hour

Since previous suggestion (2 days ago) I found 6 sales at 5 ref and 2 sales at a key

All sales were pretty fast, few hours to a day

The last suggestion had much more proof at 5 ref than any other price so I think it's enough to remove the range