1. Births: preliminary data for 2008;Hamilton;Natl Vital Stat Rep,2010
2. Deaths: preliminary data for 2008;Miniño;Natl Vital Stat Rep,2010
3. Births: final data for 2007;Martin;Natl Vital Stat Rep,2010
4. Deaths: final data for 2007;Xu;Natl Vital Stat Rep,2010
5. National Center for Health Statistics. Detailed technical notes to the United States 2007 data: natality. In: User Guide to the 2007 Natality Public Use File. Available at: ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/Dataset_Documentation/DVS/natality/UserGuide2007.pdf. Accessed September 13, 2010