1. Births: final data for 2009;Martin;Natl Vital Stat Rep,2011
2. Births: final data for 2008;Martin;Natl Vital Stat Rep,2010
3. Deaths: preliminary data for 2009;Kochanek;Natl Vital Stat Rep,2011
4. Deaths: final data for 2008;Miniňo;Natl Vital Stat Rep,2011
5. National Center for Health Statistics. Natality public use file and CD-ROM. Hyattsville, MD: National Center for Health Statistics. Published annually. Available at: www.cdc.gov/nchs/data_access/VitalStatsOnline.htm. Accessed September 19, 2011