"And make no mistake, the middle class has been ruined: Its wealth has been decimated, " ... They only lost 10% of their wealth? That's not so bad. Oh wait, they mean completely destroyed, not decimated.
But, I agree with you decimate has long had alternative meaning of "destroy almost completely"
If enough people use it that way, it becomes the correct usage, of course. It is how languages (d)evolve.
47 per cent of Americans can't raise $2000 in 30 days without selling an asset...with nearly one quarter of $100k-$150k households reporting they wouldn't be able to find $2000...Only the final one-fourth said they definitely could find a way to make the payment: http://www.huffingtonpost.com/2011/03/17/could-you-come-up-w...
The statistics cited are from the Brookings Institute: http://www.brookings.edu/~/media/Files/Programs/ES/BPEA/2011...