Answer:
Middle class
Explanation:
About 70% of all Americans consider themselves middle class. In reality however, the number is down to 50% and going down farther every year.
The belonging to middle class is measured based on income level, there are, however, many different factors that determine it farther: the level of education, access to private healthcare, employment situation, living in a specific neighborhood, cultural activities.
Middle class is slowly disappearing as the wage gap between high and low earners is getting wider. The are far more poor people than before, while the richness is in the hands of few only: big cooperations or business tycoons. Therefore, if the trends continues, there would be lower and upper class only.