I’m providing this for the research community that may want access to state historical measures of income inequality. Frank (2008) has calculated historical Gini coefficients (1916-2005), measuring income inequality. The closer the Gini coefficient is to 1 the higher the income inequality. A Gini coefficient equal to 0 represents perfect equality. Using Frank’s data I graphed each state’s Gini coefficient over time.
These coefficients appear high to me but I’ll let the experts decide that issue. Frank provides six of the most common inequality measures (Atkinson Index, Gini Coefficient, Relative Mean Deviation, Theil Index, Top 10%, and Top 1%) for each state. See the reference below for access to the data in Stata (.dta) and comma separated file (.csv) formats.
Reference
Frank, Mark W. (2008). “A New State-Level Panel of Income Inequality Measures Over the Period 1916-2005.” SHSU Economics & Int. Business Working Paper no. SHSU_ECO_WP08-02.