Government figures show that the average life expectancy in the United States reached 78 years in 2006.
The figures also show a clear drop in the number of Americans killed by eight of the 10 leading causes of death.
The largest decline in death rates between 2005 and 2006 occurred for influenza and pneumonia (12.8 percent), said the Centers for Disease Control and Prevention's National Center for Health Statistics.
Declines were also noted for chronic lower respiratory diseases (6.5 percent), stroke (6.4 percent), heart disease (5.5 percent), adult diabetes (5.3 percent), hypertension (5.0 percent), chronic liver disease and cirrhosis (3.3 percent), suicide (2.8 percent), septicemia or blood poisoning (2.7 percent), cancer (1.6 percent) and accidents (1.5 percent).
However there was an increase in Alzheimer's related-deaths, displacing diabetes as the sixth leading cause of death in 2006.
Life expectancy for a child born in 2006 was on average 78.1 years, four months longer than the 2005 average, according to the CDC figures.
Overall, the 2006 age-adjusted death rate fell to 776.4 deaths per 100,000 population from 799 deaths per 100,000 in 2005.
The 2006 infant mortality rate was 6.7 deaths per 1,000 births, a 2.3 percent decline from the 2005 rate of 6.9.
"Record high life expectancy was recorded for both white males and black males (76 years and 70 years respectively) as well as for white females and black females (81 years and 76.9 years)," the CDC said in a statement.
Also, 12,045 people died from HIV/AIDS in 2006, a 4.8 percent drop from 2005.
The data is based on a compilation of 95 percent of all US death certificates, as part of the National Vital Statistics System, the statement said.
Despite the gain in longevity, the United States is behind in life expectancy when compared to some 30 other industrialized countries.
In Japan, for example, a child born in 2006 has an average life expectancy of 83, according to World Health Organization (WHO) statistics. It is followed by Switzerland, France and Australia with more than 80 years.