There are many ways of looking at inequality statistically; one useful way to measure it across places is by using the “95/20 ratio.” This figure represents the income at which a household earns more than 95 percent of all other households, divided by the income at which a household earns more than only 20 percent of all other households. In other words, it represents the distance between a household that just cracks the top 5 percent by income, and one that just falls into the bottom 20 percent. Over the past 35 years, members of the former group have generally experienced rising incomes, while those in the latter group have seen their incomes stagnate.
The latest U.S. Census Bureau data confirm that, overall, big cities remain more unequal places by income than the rest of the country. Across the 50 largest U.S. cities in 2012, the 95/20 ratio was 10.8, compared to 9.1 for the country as a whole. The higher level of inequality in big cities reflects that, compared to national averages, big-city rich households are somewhat richer ($196,000 versus $192,000), and big-city poor households are somewhat poorer ($18,100 versus $21,000).