Federal data released Thursday shows that the infant mortality rate in the United States remains one of the worst in the developed world, at three times the rate of Japan, Norway, and Sweden and double that of Ireland.

The report from the National Center for Health Statistics, part of the Centers for Disease Control and Prevention, found that 5.96 out of every 1,000 U.S. babies died in 2013 during birth or their first year. This level was similar to the rate of 5.98 found in 2012, suggesting infant mortality has stalled.

According to World Bank figures, the 2013 rate means that the U.S. is not only outdone by "first world" nations, but also some considered "second world," including Cuba.

The CDC analysis did note that infant mortality dropped in 2013 from 6.86 per 1,000 live births in 2005.

However, the report found that the gap between white and black women is growing.

Black women in 2013 had the highest infant mortality rate in the United States at 11.11 per 1,000 births. This is more than double the rate of white women (5.06). 

Further, the report states that "the disparity in the infant mortality rate between non-Hispanic black and non-Hispanic white women has more than doubled over the past decade."

Infant mortality rates among Puerto Rican mothers were also high at 5.93 per 1,000 live births.

The CDC's findings follow a report (pdf) released last year by the Commonwealth Fund which finds that the U.S. healthcare system is the most expensive in the world yet delivers the worse care among 11 industrialized nations.