This one is, eh.

Sold for a Dead Presidents Honcho's Headgear(11 Keys with Overpay)

http://backpack.tf/profiles/76561198202046696?time=1443855600 (October 3rd)

http://backpack.tf/profiles/76561198202046696?time=1443942000 (October 4th)

http://backpack.tf/profiles/76561198140425479?time=1443942000 (October 4th)

http://backpack.tf/profiles/76561198140425479?time=1444374000 (October 9th)

Sold for a Blizzardy Storm Ol' Geezer(10 Keys with Overpay)

http://backpack.tf/profiles/76561198200970331?time=1447574400 (November 15th)

http://backpack.tf/profiles/76561198200970331?time=1447920000 (November 19th)

Sold for an Orbiting Fire Nanobalaclava(11 Keys with Overpay)

http://backpack.tf/profiles/76561198088822281?time=1448697600 (November 28th)

http://backpack.tf/profiles/76561198088822281?time=1448784000 (November 29th)

Sales seem to fit, 10-11 Keys should be fine.

Additional Proof/Counter-Proof/Constructive Criticism/Feedback is always appreciated.