Visualizing Spatial Relationships - Data Points: Visualization That Means Something - page 304

FIGurE 8-25 Unemployment rates from 2004 to 2009
It's easy to see the changes, or lack thereof, by year, from 2004 through
2006, as shown in Figure 8-26. The national average actually went down
during that time.
FIGurE 8-26 Unemployment rates 2004 to 2006
Then 2008 hits (Figure 8-27), and you start to see some of the increases
in the unemployment rate, especially in California, Oregon, and Michigan,
and some counties in the southeast.