Grid Listing Report: How to calculate a field/column total value?

how to calculate a field/column total value?

As I can understand you would like to have a total of all the numbers of a field column, currently when you have numbers in one field of your form you can only display the values submitted, but not a total of all the values submitted in this field: 

If you would like we could submit this to our second level as a feature request, please let us know and we will be glad to proceed.