Taking All indate Sales

Marketplace.tf Sales:

https://marketplace.tf/items/tf2/30490;13;strange

36.99/1.98=~18.7 keys (Jun 20th)

Median Price of Keys that day was 1.98

SCM Sales:

https://steamcommunity.com/market/listings/440/Strange%20Haunted%20Vampiric%20Vesture

https://steamcommunity.com/market/pricehistory/?appid=440&market_hash_name=Strange%20Haunted%20Vampiric%20Vesture

$32.69/2.35=~13.9 keys (May 3rd)

$51.22/2.33=~22 Keys (May 7th)

$50.37/2.31=~21.8 Keys (May 8th)

$31.48/2.16=~14.6 Keys (July 4th)

$41.07/2.19=~18.8 Keys (July 6th)

$41.07/2.24=~18.3 Keys (July 14th)

Total Sales:

13.9, 14.6, 18.3, 18.7, 18.8, 21.8, 22

Excluding Sales @13.9 and 14.6 as they look like buy order dumps on SCM.

2 new sales on SCM

$31.48/2.27=~13.9 Keys (Jul 18th)

$42.73/2.32=~18.4 Keys (Jul 19th)

Sale @13.9 appears to be a buy order dump, other sale fits range.