I created a view to compare sales during a period in the current year (CP) to the same period in the previous year (PP). It's broken down by day in a line chart.

I'd like to add some BANs that return the grand total of sales for the entire period, the previous period and the difference between the two. However, the date should not be in the view. I could just hide all days which would leave me with nothing but the grand total, but that's not feasible as the data will be updated on a monthly basis. How can I calculate the grand total so that it adjusts to my date range without having the data in the view?