Calculating average of summed values

Hi everyone,

I have a table regarding the sales of our sales reps. that has the following structure:

I would like to create an average growth of each sales rep so I can say something like "Sales rep E's sales grew by 8% while on average the sales of sales reps A-D grew by 4%".

My initial idea was to use the SUMMARIZE command to create a table like this:

...from which I was hoping to use the AVERAGE command to calculate the desired value. However, I am uncertain how to actually build a table like this with SUMMARIZE. 

Can anyone please help? Or do I even overcomplicate the issue and a simpler DAX approach is possible here?

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Here is my current DAX attempt (where I am having difficulties including the growth column):

TEST = 

ADDCOLUMNS(
    SUMMARIZE(
        Table,
        Table[Sales Rep]
    ),
    "CY",
    CALCULATE(
    sum(Table[Sales Value]),
    FILTER(
        'Date',
        year('Date'[Date]) = 2022 
    )
    ),
    "PY",
    CALCULATE(
    sum(Table[Sales Value]),
    FILTER(
        'Date',
        year('Date'[Date]) = 2021
    )
    )
)