The report by the National Center for Health Statistics summarizes information on breastfeeding rates in the United States based on data from the 1999 to 2006 National Health and Nutrition Examination Surveys. The report said the percentage of infants who were ever breastfed increased from 60 percent among infants born in 1993 or 1994 to 77 percent among infants born in 2005 or 2006.

Breastfeeding rates in 1999 to 2006 were significantly higher among those with higher income -- 74 percent compared with those who had lower income 57 percent -- even though breastfeeding is less expensive than formula feeding.

The report also said breastfeeding rates among mothers 30 years and older were significantly higher than those of mothers under 20 years.

Human milk is the ideal food for most infants and breastfed infants receive antibodies from breast milk, which protect against infection in the early postpartum period, the report said.