How to the max date of each Month for the rolling 13 Months(Monthly trend chart)

[Mazahar]

Hi All,

I need to show a rolling 13 Month of employee head count and i we have 2 fortnights( ex: 01/15/2022 and 01/31.2022  ie. Mid Month and Month end). In my trend chart i need to show Month end values for the last 12 Months and for the last month i need to show max values(it can be Mid Month or Month end). Total 13 Months i need to show in my Trend chart. How can i achieve it. 

Thank you in Advance.

Syed Mazahar