Over the years we’ve seen a variety of tools to help display graphs in Google Earth, such as GE-Graph and some 3D World Oil Consumption charts.
A new product has just been released called GraphEarth, and it’s the best looking one I’ve seen yet.
The application has a spreadsheet-style interface that makes it easy to use, and it has built-in geometry for countries, states, counties, cities and zip codes. The software itself is $24.95 and is Windows-only, but the graphs that it produces are standard KML/KMZ files and can therefore be viewed by anyone with Google Earth.
You can read more about the features of the product on their website and they have a mostly-functional 15-day free trial so you can play with it before you buy. If you need to visualize data in Google Earth, this is certainly a product to consider.