Good analysis. It means Islamabad received roughly 8000 files from 2009-2011. From 2009-2012, they completed roughly 5500 files. Assuming a nominal pre-2009 backlog of 500, we can estimate Islamabad's backlog by end 2011 to be 8000+500-5500 = 3000. If they cleared 2200 of these 3000 files by...