There have been way more sales than this.

You'll also have to use that seller as the low end.

As requested by OP, here are all instances of this with a valid sale on 'em:

http://backpack.tf/item/4494130310

http://backpack.tf/item/3990523909

http://backpack.tf/item/3964960867

http://backpack.tf/item/3320081797

http://backpack.tf/item/1123512882

http://backpack.tf/item/751723799

Sorry lad, but you'll have to track all the sales.

http://backpack.tf/profiles/76561198111274420?time=1468022400 - sale around 43 keys here

Only usable post update sale I can find. I think the suggested price here is going to be better than the current one and pretty close