##US Census Economic data
###https://www.census.gov/econ/geo-zip.html
###https://www.census.gov/programs-surveys/economic-census.html
###Census tracts seem to be smaller than zip codes particularly in urban areas, so this might be a more precise unit of data
###Problems: it may be difficult (or impossible) to determine census tract for VC, Fortune 500, and Medical Centers. ACS data by census tract is not publicly accessible.