Difference between 2 calculated fields showed as % of grand total

I have an issue in my workbook.

I've created a pivot containing values for 2011 and for 2012 in different categories. I have added 2 calculated fields to show the share. The calulated fields contain the values and I have selected "Show values as % of grand total". This gives me the share.

Now I would like to show the difference between the share in 2011 and the share in 2012. When I create a calculated field "share2012-share2011" it uses the values (instead of the share) and only shows me the difference between the values and not the share.

Example:

	2011	2012	Share2011	Share2012	Evol
ProductA	1000	1100	15%	17%	it shows me 100 but it should be 2%

Any idea how to get the correct value?

Hi dot

can you post your whole pivot table if your share is 15% & 17% then somewhere the value 6666.66 & 6470.58 will be written , i want to see that that will be easy for calculation

remove sensitive data before posting it ..

Example.xlsx

I can't post the file but I've created a small workbook that reproduces the issue I have. It's not the same number as I've posted before but it shows the issue.