Story highlights Sudden infant death syndrome declined 29%, the largest drop of the top five leading causes of infant death

Babies of non-Hispanic black women have a mortality rate more than double that of non-Hispanic white women

(CNN) Infant mortality rates have reached new lows, according to a report released by the US Centers for Disease Control and Prevention on Tuesday.

From 2005 to 2014, the infant mortality rate in the US dropped 15%, from 6.86 infant deaths per 1,000 live births to 5.82. Sudden infant death syndrome, or SIDS, declined by 29%, and there were drops in infant mortality rates across most racial groups.

"It's good news, but on the other hand, we have so much more to do," said Dr. Paul Jarris, chief medical officer for the March of Dimes, a nonprofit focused on the health of mothers and babies. "What is concerning, though, is that the inequities between non-Hispanic blacks and American Indians and the Caucasian population have persisted."

The largest drop among racial groups, 21%, was in Asian and Pacific Islander populations. All race and Hispanic subgroups experienced reductions in infant mortality rates except American Indians or Alaska Natives, among whom there was not a statistically significant change. The report shows significant declines among non-Hispanic black populations as well as women of Cuban descent.

However, those reductions were not broad enough to close the racial gap. Infants born to non-Hispanic black women have a mortality rate more than double that of non-Hispanic white women. Among Hispanic subgroups, the highest rates are seen in Puerto Ricans, 6.68 per 1,000, while the lowest, 3.95, are in populations of Cuban descent.

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