What a pain.

SALE 1

Sold for 5 keys

https://backpack.tf/profiles/76561198093846750#!/compare/1561939200/1562025600

https://backpack.tf/profiles/76561198311498888#!/compare/1561939200/1562025600

SALE 2

Don't know

https://backpack.tf/profiles/76561198311498888#!/compare/1562457600/1562544000

https://backpack.tf/profiles/76561198812290367#!/compare/1562544000/1562630400

SALE 3

Unknown

https://backpack.tf/profiles/76561198812290367#!/compare/1562630400/1566777600

https://backpack.tf/profiles/76561198333986358#!/compare/1562544000/1562630400

SALE 4

Sold for 7 keys

https://backpack.tf/profiles/76561198333986358#!/compare/1562716800/1562803200

https://backpack.tf/profiles/76561198182510127#!/compare/1557187200/1562803200

SALE 5

Don't know

https://backpack.tf/profiles/76561198216979311#!/compare/1560643200/1560729600

https://backpack.tf/profiles/76561198216979311#!/compare/1560643200/1560729600

SALE 6

https://backpack.tf/profiles/76561198349036188#!/compare/1561939200/1568246400

https://backpack.tf/profiles/76561198049845322#!/compare/1563148800/1563753600

SALE 7

Sold for 12 keys + 34.44 refined

https://backpack.tf/profiles/76561198125109310#!/compare/1560556800/1562457600

https://backpack.tf/profiles/76561198454615761#!/compare/1560470400/1560556800

Rounds to 13 keys

SALE 8

Sold for a genuine awper hand?

https://backpack.tf/profiles/76561198082812666#!/compare/1562630400/1562716800

https://backpack.tf/profiles/76561198011827547#!/compare/1562544000/1562630400

Likely other things were added..

SALE 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, & 24

Sold for 29.72 on June 14 (29.72/1.82 = 16.32 rounding to 16 keys)

Sold for 27.72 on June 23 (27.72/1.83 = 15.14 rounding to 15 keys)

Sold for 28 on June 30 (28/1.84 = 15.21 rounding to 15 keys)

Sold for 29.98 on July 1 (29.98/1.83 = 16.38 rounding to 16 keys)

Sold for 29.68 on July 8 (29.68/1.83 = 16.21 rounding to 16 keys)

Sold for 29.98 on July 13 (29.98/1.82 = 16.47 rounding to 16 keys)

Sold for 29.99 on July 28 (29.99/1.80 = 16.66 rounding to 17 keys)

Sold for 29.95 on July 30 (29.95/1.80 = 16.63 rounding to 17 keys)

Sold for 29.2 on August 5 (29.2/1.83 = 15.95 rounding to 16 keys)

Sold for 22.76 on August 6 (22.76/1.84 = 12.36 rounding to 12 keys)

Sold for 24 on August 7 (24/1.82 = 13.18 rounding to 13 keys)

Sold for 22.5 on August 8 (22.5/1.82 = 12.36 rounding to 12 keys)

Sold for 24 on August 9 (24/1.81 = 13.25 rounding to 13 keys)

Sold for 25 on August 10 (25/1.81 = 13.81 rounding to 14 keys)

Sold for 29.9 on August 12 (29.9/1.82 = 16.42 rounding to 16 keys)

Sold for 33 on August 21 (33/1.82 = 18.13 rounding to 18 keys)

https://marketplace.tf/items/tf2/30658;5;u95

History of SALE 9: https://backpack.tf/item/4253630726

History of SALE 10: https://backpack.tf/item/6941193974

History of SALE 13: https://backpack.tf/item/7752081937

History of SALE 14 https://backpack.tf/item/7421722686 (i think)

History of SALE 15: https://backpack.tf/item/4715743453

History of SALE 20, 22, & 24: https://backpack.tf/item/7698799833

SALE 25

Sold for 13 keys

https://backpack.tf/profiles/76561198052563699#!/compare/1566604800/1566777600

https://backpack.tf/profiles/76561198097271466#!/compare/1566691200/1566777600

SALE 26

Bulk for searing plasma attendant

https://backpack.tf/profiles/76561198055218916#!/compare/1563753600/1563926400

https://backpack.tf/profiles/76561198019257028#!/compare/1563840000/1563926400

SALE 27

Sold for 12 keys + 0.22 refined

https://backpack.tf/profiles/76561197986864096#!/compare/1567468800/1567728000

https://backpack.tf/profiles/76561198454615761#!/compare/1567641600/1567728000

Rounds to 12 keys

SALE 28

Sold for 13 keys + 26 refined

https://backpack.tf/profiles/76561198847672167#!/compare/1566432000/1566604800

https://backpack.tf/profiles/76561198027813272#!/compare/1566086400/1566691200

Rounds to 14 keys

SALE 29

Sold for 13 keys

https://backpack.tf/profiles/76561198254293114#!/compare/1566086400/1566172800

https://backpack.tf/profiles/76561198107557018#!/compare/1566086400/1566172800

SALE 30

Sold for 13 keys

https://backpack.tf/profiles/76561198071711499#!/compare/1564272000/1564444800

https://backpack.tf/profiles/76561198254293114#!/compare/1564358400/1564444800

SALE 31

Sold for 13 keys

https://backpack.tf/profiles/76561198932546591#!/compare/1563494400/1563667200

https://backpack.tf/profiles/76561198971152948#!/compare/1563667200/1563753600

Although, this is a scammer sale, this is supportive nonetheless.

SALE 32

Sold for 15 keys

https://backpack.tf/profiles/76561198317903441#!/compare/1566086400/1566172800

https://backpack.tf/profiles/76561198560128894#!/compare/1566086400/1566172800

SALE 33

Unknown

https://backpack.tf/profiles/76561198261849239#!/compare/1566000000/1566086400

https://backpack.tf/profiles/76561198317903441#!/compare/1565827200/1566000000

SALE 34

Sold for 13 keys + 26 refined

https://backpack.tf/profiles/76561198188754881#!/compare/1565913600/1566000000

https://backpack.tf/profiles/76561198261849239#!/compare/1565913600/1566000000

Rounds to 14 keys

SALE 35

Sold for 14 keys

https://backpack.tf/profiles/76561198096856475#!/compare/1562889600/1562976000

https://backpack.tf/profiles/76561198130524812#!/compare/1556668800/1563494400

SALE 36

Sold for 11 keys

https://backpack.tf/profiles/76561198132329942#!/compare/1565222400/1565654400

https://backpack.tf/profiles/76561198097271466#!/compare/1565568000/1565654400

SALE 37

Sold for 13 keys + 20 refined

https://backpack.tf/profiles/76561198097271466#!/compare/1566518400/1566604800

https://backpack.tf/profiles/76561198002757046#!/compare/1566518400/1566604800

Rounds to 13 keys

SALE 38

Sold for 14 keys

https://backpack.tf/profiles/76561198002757046#!/compare/1566777600/1566864000

https://backpack.tf/profiles/76561198933068263#!/compare/1566691200/1566864000

SALE 39

Unknown

https://backpack.tf/profiles/76561198202308457#!/compare/1565481600/1565740800

https://backpack.tf/profiles/76561198207835259#!/compare/1564790400/1565740800

SALE 40

Unknown

https://backpack.tf/profiles/76561198272663411#!/compare/1562544000/1566777600

https://backpack.tf/profiles/76561198105098440#!/compare/1559779200/1562544000

SALE 41

Sold for 12 keys + 40.77 refined

https://backpack.tf/profiles/76561198050518375#!/compare/1567123200/1567209600

https://backpack.tf/profiles/76561198454615761#!/compare/1567123200/1567209600

Rounds to 13 keys

CLASSIFIEDS

https://gyazo.com/ed690a02197c9cf5e9c6f3d6d81d6556

Sales at 5, 7, 11, 12, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, and 15. Marketplace sales at 12, 12, 13, 13, 14, 15, 15, 16, 16, 16, 16, 16, 16, 17, 17, and 18.

Taking 13-16 keys.