Sale 1-2:

https://marketplace.tf/items/tf2/30628;5;u56

$18 / $1.79 = 10.06 keys

$31.99 / $1.70 = 18.82 keys

Sale 3:

10 keys

sold with 15 keys for Spec KS Australium Scattergun(25)

https://backpack.tf/profiles/76561198115325995#!/compare/1570752000/1570838400

https://backpack.tf/profiles/76561198047296815#!/compare/1570752000/1570838400

scatter: https://imgur.com/a/XwfbHOb

Sale 4:

12 pure

https://backpack.tf/profiles/76561198047296815#!/compare/1572912000/1572998400

https://backpack.tf/profiles/76561197974364849#!/compare/1565222400/1572998400

Sale 5:

using for impaler

sold with 1 key + small sweets for Miami Nights Infernal Impaler

https://backpack.tf/profiles/76561197974364849#!/compare/1572998400/1573084800

https://backpack.tf/profiles/76561198086749028#!/compare/1572998400/1573084800

Sale 6:

14 pure

https://backpack.tf/profiles/76561198086749028#!/compare/1573084800/1573171200

https://backpack.tf/profiles/76561198301864750#!/compare/1572998400/1573171200

Sale 7:

untrace, possibly 1st mp sale

https://backpack.tf/profiles/76561198301864750#!/compare/1573171200/1573257600

https://backpack.tf/profiles/76561198026129220#!/compare/1573171200/1573257600

Sale 8:

untrace, possibly 2nd mp sale

https://backpack.tf/profiles/76561198026129220#!/compare/1573171200/1573257600

https://backpack.tf/profiles/76561198170590311#!/compare/1575590400/1576108800

==============================================================================

Sales:

10,10,12,14,19

19 looks like high outlier compared to other sales