各州Top 10% 家庭收入
https://www.gobankingrates.com/money/economy/how-much-you-need-to-be-in-top-10-percent-by-state/
"Sociologists Dennis Gilbert, William Thompson and Joseph Hickey estimate the upper middle class to constitute roughly 15% of the population."
https://en.wikipedia.org/wiki/Upper_middle_class?