According to the 2000 census number of US citizens native (250,314,017) and naturalized ( 12,542,626 ) is 262,856,643. http://www.census.gov/prod/2002pubs/c2kprof00-us.pdf
US citizens 65 or older: 37 million, 12% of the total population. US citizens 85 or older: 5.3 million, ~7% of the total population.
As of July 2008 The population of the US was 304,059,724 citizens.
Unless the US citizen is a Native American, all other US citizens are immigrants or descendants of immigrants. Native American make-up 1%-2% of the total US population.
3.16% of the total US population lives in Michigan.
3.69% of the total US population lives in Ohio.
1.20% of the total US population lives in Oklahoma.
According to the 1860 census:Total number of slaves in the Lower South : 2,312,352 (47% of total population).Total number of slaves in the Upper South: 1,208758 (29% of total population).Total number of slaves in the Border States: 432,586 (13% of total population).The information (which I have not checked) is here:http://civilwarcauses.org/stat.htm
It is number four in population, and number nine in total area.
0.58% of the total US population lives in Nebraska.
The number of people in the United States that play tennis numbers about 21.2 million. That is almost equal to the entire population of Australia.
2.09% of the total US population lives in Massachusetts.
1.61% of the total US population lives in Colorado.