The percentage of infant deaths from preterm-related causes increased from 34.6% in 2000 to 36.5% in 2004. Nearly half (46.3%) of the deaths of infants of non-Hispanic black mothers were preterm related in 2004,compared with 32.1% of the deaths of infants of non-Hispanic white mothers and 33.4% of the deaths of infants of Hispanic mothers. During 2000-2004, the percentage of infants born preterm increased in the United States, or from 11.6% of all births in 2000 to 12.5% in 2004.
Source: cdc.gov