Divide With a Sum and Filter on average column

[AAbdelkader]

I ask to compute attrition rate from two different data sources. I have 2 different sources:

1st: employee headcount (one row per employee) which has all employee details such as Name, ID, Date of Joining, Supervisor name, Department etc.

2nd: showing data for employees who resigned

I need to compute the attrition rate for selected Group and selected months. Groups and months will be selected from slicers.

the attrition function is: Sum of Leavers / Average monthly Headcount

and used measure unfortunately give a non-valid results

Attrition.pbix file

gratefully,

[AAbdelkader]

Dears,

please is there a solution could help me regarding to the mentioned query

thanks a lot,