While her assertions of middle class-dom clearly rub a lot of people the wrong way, US News & World Report points out, "there is no universally accepted definition of middle class." Their best guess is that the American middle class earns somewhere between $25,500 and $76,500, based on the 2012 median household income of $51,017. The mayor of New York City has declared the city's middle class to earn $47,040-$97,020 for a single person and $67,000-$138,000 for a family of four.
Yep. Sounds about right.
It would probably devolve into P&N idiocy, but I was surprised no one commented on this particular graph:
There is the an excellent example of why people say the middle class is disappearing - here is a root cause. Again, hard data, not opinion.