How to calculate average for last 3 months

[xyz2]

Hello,

I have following expression and want to calculate the average of the last three months and display it as percentage:

(count( { <[input]= {"<1"}> } [id]))
* (100)
/ (count(id))

But i dont know how to do it. I tried that but it doesn't work:

(count( { <[input]= {"<1"}, [created_date] = {"[created_date] > MonthStart(Today(),-3)"}> } [id]))
* (100)
/ (count(id))

Help is much appreciated.

Best reagrds!

[xyz2]

Help is much appreciated.

Best reagrds!