“This report from the Centers for Disease Control and Prevention’s National Center for  Health Statistics (NCHS) presents preliminary data on births and birth rates(including  births to teens and selected maternal and infant health characteristics for the  United States in 2012. The findings are based on nearly 100 percent of registered vital  records occurring in calendar year 2012, which were received and processed by NCHS as  of April 24, 2013. Trends in the preliminary reports for 1995-2011 births were confirmed  by the final vital statistics for each year. Comparisons are based on the final data  for 2011 and earlier years. Changes and differences presented in this report are  statistically significant at the 0.05 level, unless noted otherwise.”