VBA Code for Adding % Diff Column to Numerous Sheets?

Hi,

I have a huge Excel document with 1000+ sheets. Each sheet has "year" columns (2009, 2010, 2011, and 2012), and varying numbers of rows (anywhere from 1 to about 100), and I'd like to add columns to each sheet showing the year vs. year % difference.

I've attached a workbook with a before/after example. Any help on this would be greatly appreciated.

Thanks

Excel Percent Diff Example.xlsx