Calculating the average score from three diffrent tables within Power Pivot

Hi All

I was wondering whether there is an easy way to do the following:

I have a Pivot Report created from Power Pivot. This report extracts the data from 3 diffrent tables which all have a realtionship built up together. The colunns in the final Pivot are % Sales, % Perfromance and % Refunds.

What I need to do is tho claculate the average of the three columns. I cant create a measure, I was wondering whether there is a formula like GetPivot or anither way from insode the pivot table (creating a field) that I can claculate the average of three scores and then rank them.

Hope this makes sense

Thanks in advance

I have explained this wrong, what I have done is raked the percentages and then averaged them out but each component will have a different weight as Sales will have 50% and other components will have 25% each. I hope tbis is correct way of doing this.