12 month rolling year to date and month over month

[#1]

hi,

          I am displaying a pivot with year month dimension for 12 months and the business (bamount) done for this months. I am also showing the month on month variation. But am not able to show year to date variation for each of this year month combination.

For eg. if the business for 2012-01 is 100 and that for 2013-01 is 200 then the yearly variation is 100 %.

Attached is the sample doc.

Thanks in advance

Lax