Question: how to calculate growth in a pivot table?
Answer: Select cell C4 on the sheet "Pivot Table"
Go to Pivot Table Tools > Options > Fields, Items and Sets > Calculate Item. ... 
In the Name box, type Growth.
In the Formula bar, enter =('2010' /'2009' )-1 and press OK.
Select the Growth column in the pivot table and press Ctrl+Shift+5 to convert the decimals to percentages.