None are sold in the 14-16 key price range anymore, and there were 17 and 19 key offers very recently.

http://www.tf2outpost.com/trade/9787170 - B/O 20 keys

http://www.tf2outpost.com/trade/8662925 - Offer of 19 keys by |\|SS|/| Max Payne 1 day ago and 17 keys listed in C/Os

http://bazaar.tf/trade/159688 - B/O 22 keys

These were the only ones I could find.

This may be irrelevant but backpack.tf says it's cheaper than nuts n' bolts and making it 15-19 keys would make it the same as nuts, purple confetti and massed flies; all of the bonnet prices should be updated.

If 17 keys and 19 keys are being offered and buyouts are 20+ keys, it shouldn't be 14-16 basically.