The US’s high infant mortality hasn’t really dropped since 2012, according to the Centers for Disease Control and Prevention. In 2013, 5.96 infants died during their first year life out of every 1,000 live births; the year before, 5.98 babies died per 1,000 children.

The infant mortality rate is an important measure of public health in a country. The US’s infant mortality rate is the highest of the world’s top 27 wealthiest nations, despite the fact that the US spends more on health care than any other country. A baby born in America is nearly three times as likely to die during the first year than a baby born in Finland or Japan. Infants born in Cuba are likelier to live through their first year than those born in the US.

Today’s rate is 13 percent lower than in 2005, when 6.86 babies per 1,000 live births died in the first year. More than a third of infant deaths in 2013 were related to preterm births — babies born early. The CDC statistics show that babies born at 37 to 38 weeks of gestation were 63 percent more likely to die in their first year of life than babies born at full term (39 to 40 weeks).

The leading cause of infant death in the US is from congenital birth defects, followed by disorders stemming from low birthweight and short gestation. Researchers writing for the National Bureau of Economic Research think the problem has to do with the immense gap between the upper and lower classes in the United States. Infants born to white, wealthy, college-educated mothers are much more likely to survive their first year of life. That means the high infant mortality rate is almost solely driven by babies born to less advantaged mothers.