The Middle Class is shrinking, but for the right reason.

The middle class has been shrinking because they're becoming richer, not poorer as many people would have you believe. 

Also:

-"The share of “middle-income” US households annually earning between $50,000 and $100,000 in constant dollars has remained relatively stable over the last 40 years at about 30%." [1]

-"At the same time, the share of low-income households earning less than $50,000 has decreased by 13.50 percentage points from 63.6% to 50.1% from 1969 to 2009, while the share of high-income households earning more than $100,000 has increased by 14 percentage points from 6.1% to 20.1% over that period." [1]

- "middle-class households earning $50,000 to $100,000 have remained a fairly constant share of all US households over time, while there has been a significant increase in the share of high-income households that offset the decline in the share of low-income households." [1]

-Family size has shrunken over time, meaning that the average family now has more money and less people to feed.

Citation:

[1] http://www.aei-ideas.org/2014/01/census-data-on-income-distribution-reveal-evidence-of-rising-income-levels-for-a-rising-share-of-american-households/