https://marketplace.tf/items/406;14;kt-2/

April 28 - $25.00 / 1.80 = 14 keys

May 10 - $29.99 / 1.80 = 17 keys

https://marketplace.tf/items/406;14;kt-3

March 7 - $19.99 / 1.79 = 11 keys

March 31 - $50.00 / 1.79 = 28 keys

https://marketplace.tf/items/406;14/

April 16 - $29.99 / 1.78 = 17 keys

https://marketplace.tf/items/406;14;kt-1

April 19 - $2.86...

April 29 - $24.00 / 1.82 = 13 keys

https://steamcommunity.com/market/listings/440/Collector%27s%20Splendid%20Screen

March 11 - $5.09...

https://steamcommunity.com/market/listings/440/Collector%27s%20Specialized%20Killstreak%20Splendid%20Screen

March 21 - $29.99 / 2.38 = 13 keys

https://steamcommunity.com/market/listings/440/Collector%27s%20Professional%20Killstreak%20Splendid%20Screen

March 28 - $61.53 / 2.35 = 26 keys

April 3 - $8.83...

May 3 - $32.51 / 2.36 = 14 keys

https://backpack.tf/suggestion/5cdbc6b26780720b6e5a2992

Resuggestion here, using the range provided to me