Centers for Disease Prevention and Control (CDC) – Breastfeeding Practices – Results from the National Immunization Survey http://www.cdc.gov/breastfeeding/data/NIS_data/data_2004.htm

Abstract
The survey provides U.S. breastfeeding rates by year of the child's birth at early postpartum (following birth), 6 months, and 12 months. Staff and pregnant women may use this information to learn about breastfeeding practices. The national rates of breastfeeding by birth year are provided from 1999 to 2004.