Rolling 12 months total for each month of current FY and previous FY

Hi Guys,

I am new to the COGNOS world and I will highly appreciate if someone can help me with the following:

I am using a combination chart that displays the employee count as bars and the x axis has months grouped by Current FY and Previous FY. I need to calculate Rolling 12 months count for each month listed. i.e. the total of the month listed plus previous 11 months.

The issue is that the data is not displaying correctly for rolling 12 months count for the Previous FY. i.e., July 12/13 is not showing the rolling 12 months total count inclusive of the previous 11 months. It only shows the employee count for July 12/13.

I am using a dimensional data source. Expression being used is moving-total([employee count], 12)

Thanks in advance.