Click on Gross State Product (GSP) to show a choropleth map of US states by GSP: California, Texas, New York...
See the same map expressed in % by clicking on Gross State Product as percentage of national GDP: slight changes in the colors are only due to rounding.
If you click on Population, you will notice that absolute differences on GSP are mainly due to different state size in terms of population.
Finally, click on Gross State Product per capita to get a map of US states by a relative measure of production: DC, Delaware, Alaska, Connecticut, Wyoming...
This sample code uses JSON-stat + Visual to create a choropleth map of the US population and Gross State Product.
The data are retrieved from us-gsp.json. The US map is one of the sample maps provided by Visual.
See also the simple choropleth map example or the population pyramid example.
Warning: This visualization does not work on Internet Explorer < 10: version 9 seems to be unable to process the JavaScript US map (2,490 kb).