While most common use (albeit not correct) of the word decimate is to 'completely obliterate or crush', it is incorrect. It actually means to fractionally dispose of or destroy. It comes from Roman punishment in which they executed every tenth soldier. So, when something takes a fraction (no longer necessary to be exactly one tenth) of something, it's ok to use decimate, such as 'H1N1 decimated population in 2010'. But you cannot say 'Hurricane Rita decimated New Orleans.' The word you are looking for here is 'destroy, obliterate, wipe, etc.