Hi,
If you post your sample file or tell about your fields then it's more possible to help you. But please try this if you have a date field then take the month of the date field using one load and take the sum(ClosedCall) group by month.
If you want to achieve using the chart then give month as dimension and sum(ClosedCall) in the expression.
If there is no direct fields like this in your application please post your sample file
