(Made a mistake in using the wrong Steam market link.)

Strange Dovetailed War Paint (Factory New)

https://steamcommunity.com/market/listings/440/Strange%20Dovetailed%20War%20Paint%20%28Factory%20New%29

Sales under 10 keys so I'm not including them.

https://marketplace.tf/items/tf2/17224;11;w1;pk224

Dividing by the average price of a key on that day.

1 sold on January 17th, 2020:

$11.52/$1.77 = 6.51 ~ 6.5 keys

1 sold on January 20th:

$18.45/$1.78 = 10.37 ~ 10.4 keys

1 sold on March 18th:

$19.45/$1.69 = 11.51 ~ 11.5 keys

Taking 10.4 - 11.5 keys as the range.