Sale 1:

https://backpack.tf/profiles/76561198273732193#!/compare/1525910400/1525996800

https://backpack.tf/profiles/76561198060212574#!/compare/1525910400/1525996800

Sold with ~5 keys in sweets for Burning Trencher(75)

http://www.tf2outpost.com/trade/29640748

B/O of 90 keys.

Total is 70 keys.

Sale 2:

https://backpack.tf/profiles/76561198060212574#!/compare/1527379200/1527465600

https://backpack.tf/profiles/76561198144945119#!/compare/1527379200/1527465600

Sold for Vivid Noir + Stormy Larrikin(13) + ST Most Wanted(6.25)

Noir Mini:

https://backpack.tf/suggestion/5b198dd0cf6c7572b270d206

Suggestion for 22 keys

Total is 22 + 13 + 6.25 = 41.25 keys

Sale 3:

https://backpack.tf/profiles/76561198144945119#!/compare/1527984000/1528070400

https://backpack.tf/profiles/76561198026198026#!/compare/1527984000/1528070400

Sold for keys, can only trace 17, maybe more were used?

Sale 4:

https://backpack.tf/profiles/76561198026198026#!/compare/1528156800/1528416000

https://backpack.tf/profiles/76561198096247397#!/compare/1528070400/1528416000

Sold for 51 keys through Scrap Auction.

Sale 5:

https://backpack.tf/profiles/76561198096247397#!/compare/1528416000/1528588800

https://backpack.tf/profiles/76561198118254940#!/compare/1528502400/1528588800

Sold with ~11 keys in sweets for PE Conq + Beams Toque

Conq Mini:

https://backpack.tf/suggestion/5b1ceaed44325a0f7864888a

Suggestion for 50 keys

Toque Mini:

https://backpack.tf/suggestion/5b27f551cf6c7538171e36cd

Suggestion for 41 keys

Total is 91 - 11 = 80 keys.

Total sales @:

17, 41.25, 51, 70, 80

https://i.imgur.com/X8XyAFb.jpg

Seller for 75 keys

Considering seller, calling 80 the outlier.

I'm also gonna justify not putting 70 in the range as it is the oldest sale, so in the effort of using sales within a month,

taking 41 - 51 keys.