Old school D3 from simpler times
Small Multiple Choropleth Map
Small multiples choropleth map. Color shows the annual percent change in
the number of manufacturing jobs. Red is a decline, blue is growth.
Three recessions are covered in this timespan: July 1990 to March 1991,
March 2001 to November 2001, and December 2007 to June 2009
(see NBER's business cycle dates).
In a real world situation you wouldn't want to have the user's browser
do all the computation needed to draw these maps.
The maps are rendered in
so it would be fairly straightforward to pre-render them as images
and to serve those instead.
Source: Bureau of Labor Statistics' QCEW program