PivotTables are a good way to go. While this is the end of the golf season, if you are going to be doing this again next year, a PivotTable is definitely the best way to go.
You can add new data after each game and with a right click on the pivot table, "refresh" to pick up the new information and recalculate.
You can also auto generate row totals/averages, ie (oops I forgot to change the column header text):

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Do the scores relate to more than one golf course? It looks like Tommy Bahama may have played a couple of different coursed (based on "slope", what ever that is). You could add the course names to the pivottable.
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In this example I added a course column, and filtered the output to show only "Course B"

Andreas:
Just curious, why didn't you turn the input data into an Excel Table? How did you not turn it?