If you look at the details of those statistics, you'll find that incomes were rising for taxpayers in most income brackets. The group that was DOWN and accounted for practically ALL of the statistical decline in national income was the evil 2% at the top -- those in the over $200K income bracket.
I don't know why I can't find the stats I'm looking for as there were several articles quoting the same IRS figures. Lob Dobbs, who is the best pundit on the subject had one as well as Fox News. I think Wall Street Journal did as well.