Where can I find a rich dataset for testing visualization software?

I am developing a ASP.Net data visualization web application similar to google analytics and I need a rich dataset to test it with. The application allows data visualization by state and over time.

I am hav开发者_运维问答ing trouble finding a rich dataset and do not know who to ask.

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You can try to find something useful here, which is what I do, when I need sample data. It's the website of the german ministry of statistics. For example this link shows the increase in price for consumer goods since '05.

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How about Microsoft's Northwind or AdventureWorks sample databases ? More samples here