Population--Arizona by Decade
For decennial census from 1900- 1990 visit the U.S. Census Bureau Population Census Counts page: www.census.gov/population/www/censusdata/cencounts/index.html
For more current information visit the U.S. census Arizona QuickFacts page: quickfacts.census.gov/qfd/states/04000.html
"Population of Counties by Decennial Census." U.S, Census Bureau. http://www.census.gov/population/www/censusdata/cencounts/files/az190090.txt (accessed October 4, 2011).
"Arizona QuickFacts from the US Census Bureau." State and County QuickFacts. http://quickfacts.census.gov/qfd/states/04000.html (accessed October 4, 2011).