January 1, 2009 estimate: 5,688,000.
Increase of 324,000 since 2000 (6%).
Growth is primarily taking place in four areas of the state
1. Fox Valley, the Brown-Outagamie-Winnebago stretch of counties.
2. "Western Wisconsin", which I assume means St. Croix County.
3. Dane County. (The pace has definitely slowed down considerably, but new homes are still being built here.)
4. Southeastern Wisconsin. (Waukesha, Washington, and Kenosha counties from what I can gather).