The life expectancy for Americans is nearly 78 years, the longest in U.S. history, according to new government figures from 2005 released Thursday.

U.S. life expectancy at birth inched up to 77.9 years from the previous record, 77.8, recorded for 2004. Only 10 years earlier, in 1995, life expectancy was 75.8, and in 1955 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, which released the new life expectancy report Wednesday.

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

The annual number of U.S. deaths rose from 2004 to 2005, after the figure had dropped by 50,000 from 2003 to 2004. In 2005, the number of deaths increased by about that same amount.

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

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

A final report will be released later, and the numbers may change a little. Last year, when releasing its preliminary death data for 2004, the government reported a 77.9 life expectancy. That figure later dropped to 77.8 in the final report.

In the 2005 preliminary report, researchers counted 2,447,910 deaths, up about 2 percent from the 2,397,615 in 2004.

The 2004 count had been a 2 percent drop from 2003 — the biggest decline in nearly 70 years.

Researchers also noted continued differences by race and sex. Life expectancy for whites in 2005 was 78.3, the same as it was in 2004. Black life expectancy rose from 73.1 in 2004 to 73.2 in 2005, but it was still nearly five years lower than the white figure.

Life expectancy for women continues to be five years longer than for men, the report also found.

The age-adjusted death rate for heart disease dropped from 217 deaths per 100,000 in 2004 to about 210 in 2005, and actual deaths dropped from about 652,500 to about 649,000. The stroke rate dropped from 50 per 100,000 to about 46.5, and the number of stroke deaths dropped from about 150,000 to 143,500.

But the count of cancer deaths rose from about 554,000 to about 559,000, according to the report.

And there were 5 percent increases in the rates for Alzheimer's disease, the No. 7 leading cause of death, and for Parkinson's disease, which was No. 14.

The United States continues to lag behind at least 40 other nations in life expectancy. Andorra, a tiny country in the Pyrenees mountains between France and Spain, has the longest life expectancy, at 83.5 years, according to the U.S. Census Bureau. Japan, Macau, San Marino and Singapore ranked second, third, fourth and fifth.