U.S. life expectancy plunged by nearly three years in the first two years of the COVID-19 pandemic, according to a government report released Wednesday.

It was 78 years, 10 months in 2019. In 2020, it dropped to 77 years. Last year, it fell to about 76 years, 1 month, according to the U.S. Centers for Disease Control and Prevention (CDC).

The last time it was that low was in 1996. And the last comparable decrease happened in the early 1940s, during the height of World War II.

Life expectancy is an estimate of the average number of years a baby born in a given year might be expected to live, given death rates at that time. It is "the most fundamental indicator of population health in this country," said Robert Hummer, a University of North Carolina researcher focusing on population health patterns.

U.S. life expectancy rose for decades, but progress stalled before the pandemic.

CDC officials blamed COVID-19 for about half the decline in 2021, a year when vaccinations became widely available but new coronavirus variants caused waves of hospitalizations and deaths. Other contributors to the decline are longstanding problems: drug overdoses, heart disease, suicide and chronic liver disease.

"It's a dismal situation. It was bad before and it's gotten worse," said Samuel Preston, a University of Pennsylvania demographer.

Situation worse for some racial groups

Declines during the pandemic were worse for some racial groups, and some gaps widened. For example, life expectancy for Indian and Alaskan Native Americans saw a decline of more than 6 1/2 years since the pandemic began, and is at 65 years. In the same span, life expectancy for Asian Americans dropped by about two years, and stands at 83 1/2.

Experts say there are many possible reasons for such differences, including a lack of access to quality health care, lower vaccination rates, and a greater share of the population in lower-paying jobs that required them to keep working when the pandemic was at its worst.

The new report is based on provisional data. Life expectancy estimates can change with the addition of more data and further analysis. For example, the CDC initially said life expectancy in 2020 declined by about 1 year 6 months. But after more death reports and analysis came in, it ended up being about 1 year 10 months.

But it's likely the declines in 2020 and 2021 will stand as the first two consecutive years of declining life expectancy in the U.S. since the early 1960s, CDC officials said.

(With input from AP)