The problem is not confined to the Rust Belt or Appalachia. In fact, the middle is shrinking from coast to coast.
The change is not just a consequence of people getting poorer. Rather, the study found that while some Americans are falling from the middle to the lower class, others are rising from the middle into the upper-income households.
Pew defines middle-income households as those having three people and an annual income between about $42,000 to $125,000, adjusted for the cost of living in a metro area and the number of household members. Overall, between 2000 and 2014, “the share of adults in the upper-income tier increased from 17 percent to 20 percent, and the share of adults in the lower-income tier increased from 28 percent to 29 percent,” Pew said.