Count eVar values and create averages - Please help

[Simon_Pilkowski]

Hi everyone,

I´m currently struggling with a task, what I would have thought will be easy to solve. Maybe someone can help or finally tell me, that what I need is not possible with Adobes Online tools or using Discover. I know this can be done using Report Builder , Excel Exports, the API or using our BI Tools but I would like to achieve this using Adobes default tools for basic reporting users.

Here an Example of data I have (made up):

eVar1                                    Instances
Retailer 1                                         10
        eVar2                                       10
        RetailerCustomer1                    4  
        RetailerCustomer2                    3
        RetailerCustomer3                    3

Retailer 2                                         20
        eVar2                                       20
        RetailerCustomer1                  12  
        RetailerCustomer2                    8

Retailer 3                                         30

        eVar2                                       30
        RetailerCustomer1                  10  
        RetailerCustomer2                  10
        RetailerCustomer3                  10

How can I create a calculated Metric which will give me the amount of customers per Retailer? In my example:

eVar1                Amount of RetailerCustomers      
Total                                                   8                                                
Retailer 1                                           3                                                
Retailer 2                                           2                                                
Retailer 3                                           3                                              

In addition I would like to see trended amounts of total Retailers (in given example 3) & Retailcustomers (in given example 8).
I´m looking forward to your feedback and hopefully someone can help with a Calculated Metric I have not figured out yet.
One thing i have tried is to use Row Count with eVar2 Instances but when using this Metric on a trended report (12 months) I get a value of 12 which corresponds to the amount of rows (12 months) for every month.

Please someone tell me there is something I have failed to see ;)

Thanks in advance 
Simon