Resuggestion, thanks to Polar for the info!

Sale 1:

https://backpack.tf/profiles/76561198079363927#!/compare/1564617600/1564704000

https://backpack.tf/profiles/76561198362008411#!/compare/1564617600/1564704000

Sold for 28 keys

Sale 2:

https://backpack.tf/profiles/76561198030383222#!/compare/1562976000/1563062400

https://backpack.tf/profiles/76561198160856661#!/compare/1562976000/1563062400

Bulk

sale 3:

https://backpack.tf/profiles/76561198157315119#!/compare/1567382400/1567468800

https://backpack.tf/profiles/76561198080179568#!/compare/1567296000/1567382400

Bulk

sale 4:

https://backpack.tf/profiles/76561198080179568#!/compare/1567555200/1567641600

https://backpack.tf/profiles/76561198271892201#!/compare/1567555200/1567641600

Sold for 34 keys

sale 5:

https://backpack.tf/profiles/76561198271892201#!/compare/1567987200/1568073600

https://backpack.tf/profiles/76561198005070905#!/compare/1567987200/1568073600

https://backpack.tf/profiles/76561198080179568#!/compare/1567987200/1568073600

Bulk then QS

Sale 6:

https://backpack.tf/profiles/76561198051680717#!/compare/1568592000/1568678400

https://backpack.tf/profiles/76561198043936328#!/compare/1568592000/1568764800

Bulk / Untrace

Sale 7 - 9:

https://marketplace.tf/items/tf2/110;5;u57

$62.99 / $1.82 = 34.61 keys <-- https://backpack.tf/item/2328955918 | https://bot.tf/stats/listings/Y8ENGWZX B/O of 40 keys

$69.99 / $1.81 = 38.67 keys <-- https://backpack.tf/item/3344196690 | https://bot.tf/stats/listings/4KR02ERE B/O of 42 keys

$48.47 / $1.81 = 26.78 keys

Sale 10:

https://backpack.tf/profiles/76561198160856661#!/compare/1566604800/1566691200

https://backpack.tf/profiles/76561198157315119#!/compare/1566604800/1566691200

Sold for 72 Boston + ~1.5 keys in sweets + 35 keys

https://i.imgur.com/aNViAgX.png

Boston Mini:

https://backpack.tf/suggestion/5d8c623ed3817270103bdd28

Suggestion for 3.5 keys

total is 40 keys

https://bot.tf/stats/listings/4W6153NZ

B/O of 40 keys

Total sales @:

26.78, 28, 34, 34.61, 38.67, 40 keys

buyers up to ~29 keys,

seller for 36 keys, unsold for 2 weeks,

calling 28 and under low,

Polar's Part:

Unsold still there and sale 5 had a b/o of 29 - https://bot.tf/stats/listings/MVRNN3JV

Honestly, I would probably call two outliers on either end and go 34-35

https://backpack.tf/suggestion/5d8c62f7d381726efa1dd66e

Linking previous suggestion for more in-depth comment from Polar.