1. Deaths: final data for 2005. Centers for Disease Control;Kung;Natl Vital Stat Rep,2008
2. US Census Bureau, population division. Table 2. Projections of the population by selected age groups and sex for the United States: 2010 to 2050 (NP2008–T2). Release date August 14, 2008. Available at: http://www.census.gov/population/www/projections/files/nation/summary/np2008-t2.xls. Accessed September 2, 2009.
3. US Census Bureau, population division. Table 3. Percent distribution of the projected population by selected age groups and sex for the United States: 2010 to 2050 (NP2008–T3). Release date August 14, 2008. Available at: http://www.census.gov/population/www/projections/files/nation/summary/np2008-t3.xls. Accessed September 2, 2009.