В вашей же выдержке говорится "who commonly reside in households with six figure incomes"И из той же википедии "Certain professions can be deemed as "upper middle class" in nature although any such measurement remains somewhat subjective because of differing perceptions of class. Most people in the upper-middle class strata are highly educated white collar professionals such as doctors (physicians US), economists, accountants, university professors (lecturers UK), architects, consultants, scientists, engineers, dentists, non-corporate business owners, upper management civil servants and the intelligentsia. Generally, people in these professions have earned an advanced post-secondary education and a comfortable standard of living. In most cases household incomes can range from $150,000 to $250,000 a year or more. [1]"