Median and Mean Household Income at the County Level back to 1990

Question

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

Answer 1

Estimate-based data for mean and median household income at the county level is available for: 1990, 2000, 2005-2009, 2006-2010, 2007-2011, 2008-2012, 2009-2013, 2010-2014 ( and 2011-2015 in Dec. 2016). American Factfinder is a good resource for these estimates. NHGIS is a good resource for processed Census data that is GIS-friendly.

Model-based data for median household income at the county level is available through SAIPE.

Answer 2

1990 Census of Population: Social and Economic Characteristics (page 410) http://www2.census.gov/library/publications/decennial/1990/cp-2/cp-2-34-1.pdf

Table QT-P32 Income Distribution in 1999 of Households and Families: 2000, Census 2000 Summary File 3 (SF 3) - Sample Data http://factfinder.census.gov/bkmk/table/1.0/en/DEC/00_SF3/QTP32/0400000US36.05000

2009-2014 earnings in last 12 months: http://factfinder.census.gov/faces/tableservices/jsf/pages/productview.xhtml?pid=ACS_14_5YR_S1901&prodType=table