Interested in measuring the spread between the median and mean household income in New York County (aka Manhattan) going back to 1990. Where can I get median and mean household income at the county level going back 20 years?
Sources I've found:
Here is median income for NY State for that time period: http://www.statista.com/statistics/205974/median-household-income-in-new-york/
ACS has this info, but only back to ~2009: https://factfinder.census.gov/faces/tableservices/jsf/pages/productview.xhtml?pid=ACS_14_5YR_S1901&prodType=table