A choropleth map of infant mortality rates by county from 1999-2015.
Source: CDC WONDER Compressed Mortality, 1999-2015.
WONDER exports tab-separated values which are loaded and parsed with d3.tsv. To make the file compatible, remove all the rows after and including "Total".
Part of an exploration in American mortality trends with Debby Oh.
Based on Choropleth by Mike Bostock.