ATLANTA — The life expectancy for Americans is nearly 78 years, the longest in American history, according to new government figures from 2005 released yesterday.

That age, based on the latest data available, was still lower than the life span in more than three dozen other countries, however.

More bad news: The annual number of American deaths rose between 2004 and 2005, a depressing uptick after the figure had dropped by 50,000 between 2003 and 2004. In 2005, the number of deaths increased by about that same amount.

The American life expectancy at birth inched up to 77.9 from the previous record, 77.8, recorded for 2004. The increase was more dramatic in contrast with 1995, when life expectancy was 75.8, and 1955, when it was 69.6.

The improvement was led by a drop in deaths from heart disease and stroke — two of the nation’s leading killers, according to the National Center for Health Statistics.

“If death rates from certain leading causes of death continue to decline, we should continue to see improvements in life expectancy,” a survey statistician who coauthored the report, Hsiang-Ching Kung, said in a prepared statement.

The report also described a slight increase in the infant mortality rate, to 6.9 for every 1,000 live births in 2004 to 6.8 in 2005. But researchers said the increase was not statistically significant.

The report is based on about 99% of the death records reported in all 50 states and the District of Columbia for 2005.