i asked google, and saw that number-and more than once, including from INS. it's down from a high of 12 million or so in 07. perhaps your site includes legal immigrants?
at any rate, this thread got me thinking, and searching...and i found this:
http://www.cis.org/articles/2004/fiscal.pdf
still in the process of reading it, but it certainly is enlightening thus far. i was unaware just how much of a financial drain that illegals are on the federal budget; one would have to assume that it's a drain on state budgets as well-for those experiencing high levels of illegals in their state. no doubt scuds will chime in on this altho california has other issues as well, such as education in that state making up 40% of the total budget costs, and retirement pay for govt workers being incredibly high.