OTBI Report not showing the person, who is been resigned or terminated on the last day of the month.

I have created an OTBI Report named 'Attrition Report', This Report will calculate the attrition percentage between the given dates (The date is dynamic and been inputted by the user).
The report has column such as Period_start_headcount, Period_end_headcount, Average_Period_headcount, Resignation_Headcount (Sum of resignation and Termination) and Attrition%(The attrition% is calculated based on the above column). And have multiple prompts including Job_Name, Department_Name, Calendar_Month_start_date, Calendar_Month_end_date, Worker_Category.(In the prompt we have not used termination date because while using the termination_date all the headcount value becomes zero