You can use the eVar2 Instances metric. E.g. if your eVar2 is named "Customer interaction", then this metric is called "Customer Interaction Instances". An instance is a count of the number of times that the eVar had been set with a value, and does not count any subsequent persistences. So in your case, since your eVar2 is tracked when the user clicks the button panel or radio button, then the eVar2 instance returns the count of those clicks.