Resuggestion, thanks to Blaze for the info!

Sale 1:

https://backpack.tf/profiles/76561198025199560#!/compare/1542326400/1542672000

https://backpack.tf/profiles/76561198819564432#!/compare/1542326400/1542412800

Sold with ~4 keys in sweets for Flies Drill

Use there

Sale 2:

https://backpack.tf/profiles/76561198819564432#!/compare/1542412800/1542499200

https://backpack.tf/profiles/76561198343183806#!/compare/1542412800/1542499200

ALT transfer?

Sale 3:

https://backpack.tf/profiles/76561198343183806#!/compare/1542499200/1542585600

https://backpack.tf/profiles/76561198010309028#!/compare/1542499200/1542585600

Sold with ~7 keys for OF Baker

Use there.

Sale 4:

https://backpack.tf/profiles/76561198010309028#!/compare/1542758400/1542844800

https://backpack.tf/profiles/76561198058730344#!/compare/1542758400/1542844800

Sold for N&B Toe + ~1 key in sweets

Toe Mini:

https://backpack.tf/suggestion/5c33f470cf6c752f5521db1a

Suggestion for 7.5 keys

Total is 8.5 keys

Sale 5:

https://backpack.tf/profiles/76561198058730344#!/compare/1543017600/1543276800

https://backpack.tf/profiles/76561198418740133#!/compare/1543190400/1543276800

Bulky

Sale 6:

https://backpack.tf/profiles/76561198418740133#!/compare/1544918400/1545004800

https://backpack.tf/profiles/76561198321085442#!/compare/1544918400/1545004800

Untrace

Sale 7:

https://backpack.tf/profiles/76561198030066149#!/compare/1545091200/1545177600

https://backpack.tf/profiles/76561198246165068#!/compare/1545091200/1545177600

Bulk

Sale 8:

https://backpack.tf/profiles/76561198246165068#!/compare/1545350400/1545436800

https://backpack.tf/profiles/76561198125719539#!/compare/1545350400/1545436800

Sold for ~10 keys

Sale 9:

https://backpack.tf/profiles/76561198125719539#!/compare/1545523200/1545609600

https://backpack.tf/profiles/76561198249230496#!/compare/1545523200/1545609600

Sold for TW Bombing

Bombing Mini:

https://backpack.tf/suggestion/5c3453e5cf6c75055f48ee5f

Suggestion for 9.5 keys

Sale 10:

https://backpack.tf/profiles/76561198249230496#!/compare/1545782400/1545868800

https://backpack.tf/profiles/76561198355143414#!/compare/1545696000/1545868800

Bulk

Sale 11:

https://backpack.tf/profiles/76561198355143414#!/compare/1545868800/1545955200

Bulk

Sale 12, 13:

https://marketplace.tf/items/179;5;u60

Sold for 20, 21.47 USD

Keys at 1.78, 1.78 USD

Totals are 11.24, 12.06 keys

Sale 14:

https://backpack.tf/profiles/76561198315588518#!/compare/1548288000/1548374400

https://backpack.tf/profiles/76561198074795733#!/compare/1548201600/1548374400

for ~8.5 keys

Total sales @:

8.5, 8.5, 9.5, 10, 11.24, 12.06 keys

Buyers up to 8 keys,

new seller at 8.5 keys,

Taking 8.5 to 12 keys

Blaze's Part:

sale 9 sold with a key as well which can be seen in the second compare link putting the sale at 8.5 keys.

including 8.5 would probably be better.