Copying info from y3ezz's suggestion. All credits to them!

(Sorry if you did the work already and were gonna post)

Copied info:

sale 1)

sold along with ~12 keys of sweets for a duped darkblaze pom-pommed provocateur (79)

https://backpack.tf/profiles/76561198258264645#!/compare/1523664000/1523750400

https://backpack.tf/profiles/76561198107368363#!/compare/1523577600/1523750400

79 pom - 12 keys of sweets = 67 keys

pom-pom mini

sold for a clean spellbound nanobalaclava (77) + ~2 keys sweets

https://backpack.tf/profiles/76561198012186549#!/compare/1517011200/1517184000

taking 79 on the pom

sale 2)

bought for $168.91 via SCM

https://backpack.tf/profiles/76561198107368363#!/compare/1519430400/1523232000

https://steamcommunity.com/market/listings/440/Unusual%20Pardner%27s%20Pompadour

= 69 keys

My own addition:

Sale 3:

https://backpack.tf/profiles/76561198065409820#!/compare/1523750400/1523923200

https://backpack.tf/profiles/76561198258264645#!/compare/1523836800/1523923200

Sold for Blizzardy Bombing Run(12.5) + Stormy Liquidator's + CPS Pith Helmet + N&B Cotton Head + 2 keys + 19.25 keys in sweets.

https://backpack.tf/profiles/76561198053270115#!/compare/1523836800/1523923200

Cotton Head sold within 30 minutes for 17 keys pure, taking that, as it's what the seller expected to get.

https://backpack.tf/profiles/76561198110597187#!/compare/1523750400/1523923200

Pith Helmet sold for 14 keys pure within the same time frame as Cotton Head, taking 14 for same reason.

Lid Mini:

https://marketplace.tf/items/779;5;u29

Sold for 27.99 USD, keys @ 14.21 keys

Total is 12.5 + 17 + 14 + 14.21 + 19.25 + 2 = 78.96 keys

Sale 4:

https://backpack.tf/profiles/76561198065409820#!/compare/1524268800/1524355200

https://backpack.tf/profiles/76561198055063451#!/compare/1523923200/1524355200

Sold for 71 pure.

Total sales are:

67, 69, 71, 78.96

Calling 78.96 an outlier, taking 67 - 71 keys