In fact, the whole notion of a shrinking middle class is a myth. Here's why.

When you compare household incomes over time, you have to look at identical households. The census defines a household as one or more persons living in the same abode. Fifty years ago, only 15% of all U.S. households had a single occupant. By 2017 that percentage had nearly doubled, to 28% percent. In just the last 10 years, the percentage has increased by three points. So, the typical household today is much smaller.

https://www.google.com/amp/s/www.latimes.com/opinion/op-ed/la-oe-schiller-shrinking-middle-class-20190131-story.html%3f_amp=true