(AP) -- U.S. life expectancy has hit another all-time high, rising above 78 years.
The estimate of 78 years and 2 months is for a baby born in 2009, and comes from a preliminary report released Wednesday by the Centers for Disease Control and Prevention.
About 2.4 million people died in the United States in 2009 - roughly 36,000 fewer deaths than the year before.
Deaths were down for a range of causes, from heart disease to homicide, so experts don't believe there's one simple explanation for the increase in life expectancy. Better medical treatment, vaccination campaigns and public health measures against smoking are believed to be having an impact.
U.S. life expectancy has been generally increasing since at least the 1940s, though some years it held steady and a few times it temporarily dipped.
Previously, the CDC said a one-month dip occurred in 2008 to 77 years and 11 months. But in Wednesday's report, the agency corrected that to 78 years, attributing the glitch to a computer programming error.
Belatedly, "we realized there's something wrong here" in the 2008 estimate, said Ken Kochanek, a CDC statistician.
The 2009 report by the CDC's National Center for Health Statistics is based on nearly all the death certificates for that year. A final report is due later this year.
More good news from the new report: The infant mortality rate hit a record low of 6.42 deaths per 1,000 live births, a drop of nearly 3 percent from 2008.
But not everyone benefitted. While life expectancy for whites rose, it held steady for blacks. The infant mortality rate for black babies did not improve either.
As a result, the racial gap got a little wider. Whites already live about four years longer than blacks, and the margin grew by about two months.
The gap between the sexes also persisted. Overall male life expectancy is roughly 75 1/2 , for females it's about 80 1/2.
Other highlights from the 2009 report include:
- Death rates declined slightly for 10 of the 15 leading causes of death, including heart disease, cancer, stroke, accidents, Alzheimer's disease, homicide and influenza and pneumonia.
-Suicide passed blood infections to become the 10th leading cause of death. Suicide rates did not change significantly, but the blood infection death rate dropped nearly 2 percent. That puts suicide back in the top 10 causes of deaths for the first time since 1999, Kochanek said.
-The influenza/pneumonia death rate dropped nearly 5 percent, even though 2009 was the year that the swine flu pandemic hit.
Flu deaths rose by about 1,000 in 2009 from the year before, but pneumonia deaths dropped by nearly 4,000. Pneumonia is a flu complication most often seen in the elderly, and is a main reason why the overwhelming majority of flu-related deaths most years occur in the elderly. But while swine flu hit young adults and kids unusually hard, it caused relatively mild illness for people 55 and older.
"The irony is there were less deaths because the elderly were spared in this pandemic," said Dr. Keith Klugman, a professor of global health at Atlanta's Emory University.
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