The US Constitution’s Article I, Section 2 requires a national census every ten years - and the time has come again in 2010. Accordingly, this month the US Census Bureau mailed 120 million forms to households nationwide, and completed forms have begun streaming back. Because this count determines the distribution of more than $400 billion in annual spending and representation in the House of Representatives, local and state governments and media watch mail participation rates very closely (as do many data geeks like myself).

To keep up with all this interest, the Census Bureau is providing daily updates on the participation rate by state, county, and census tract — well over 100,000 distinct geographical entities throughout the 50 states and Puerto Rico. To make this huge amount of data easy to browse, for the first time the Census is plotting it with Google Maps. Check out the Take 10 Map for yourself. What you’ll see is a basic accounting of the percentage of forms that have been received back by region (not by household). None of the results of the survey are shown — that data is not revealed at the household level, and aggregate data won’t be made available for several months.

Additionally, this same data from the Census Bureau is available as a layer for use in Google Earth. You can download the layer for use in your desktop client. You can even embed the layer within your website or share with a friend, just like below. Simply click the “Get Link or Embed” link, tweak the settings to your preferences, and you’ll get the code to send a link or embed in your site -- no permission needed.

In the same spirit as the Take 10 Map and Google Earth layer, we’re also working with the Census Bureau to make their volumes of data more accessible through technologies like Public Data Explorer and the experimental Fusion Tables. If you’re a developer who plots data on maps, we also whipped up some pretty useful border simplifications and regionations for this layer that we plan to make freely available in the near future. And if you’re just interested in looking at pretty maps made with Census data, you’ll definitely want to take a look at some really old ones.

Posted by Jesse Friedman, Product Marketing Manager