This can be done using a Table calculation. Right click on Sum(Unique Visitors) and select Add Table Calculation... Select Percent From in the Calculation Type. Calculate the percentage along the Table(Down) and Display the value as a percentage of Previous. Hope this helps!
Hi Tracy thanks for your answer... maybe I was not clear enough... here is the table I would like to build, The calculation of Sp (Enroll and Thanks) is one thing and the calculation for "En" (Enroll and Thanks) another one. I also want to see these percentages on a different column is possible, so I would be able to see the original values as well. Thanks so much for your response.
Tracy if you can help me with this would be fantastic. Please :-)