If this is 31% of the population, middle class is basically defined as everyone/90% with 9% poor and %1% rich. Worthless. Just talk about percentile. Obviously the top 10% we talk about here is just simply rich.
Think of the economy as the solar system and mass as money
Asteroids: Wage slaves
Earth: Middle class
Jupiter: Celeberties
The Fucking Sun: 10 tech dweebs who own all the AI