Average of Sum of Columns

[chiso_chiso]

On a straight table I have a column (Total Sales)  made of sum(ColumnA) + Sum(ColumnC) + Sum(ColumnE). Please assist as I want the average of Total Sales. My data is coming from an excel sheet.

[alexandros17]

in the expression page you find 3 radio buttons, THe lower (which shows Sum by defaut) has even Average of rows, try with that setting

[chiso_chiso]

Sorry my question was incomplete.

I want the result as a percentile of 40. In simplest terms sum(Total Sales)/count(Total Sales)/40 where Total Sales is made up of Column A + Column C + Column E. I would expect a in Column A 5 rows, Column C 12 Rows and Column E 3Rows