1. Apelbaum Consulting Group (ACG), 2007. unpublished data.
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3. Australian Bureau of Statistics (ABS). Australia Historical Population Statistics, 2004b 〈http://www.abs.gov.au/〉. Accessed April 18, 2006.
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5. Bureau of Transportation Statistics (BTS). National Transportation Statistics. 〈http://www.bts.gov/publications/national_transportation_statistics/〉. Accessed January 27, 2006.