This is the worst year in the history of the United States, with deaths predicted for the first time to top 3 million, primarily due to the coronavirus pandemic.

This year’s final mortality data will not be available for months. However, preliminary estimates show that this year, the United States is on track to see more than 3.2 million deaths or at least 400,000 more than in 2019.

Most years, U.S. deaths rise, so a certain annual increase in fatalities is expected. But the figures for 2020 equate to a leap of around 15% and could go higher after all of this month’s deaths are counted.

Since 1918, when tens of thousands of U.S. soldiers died in World War I and hundreds of thousands of Americans died in a flu pandemic, that would be the largest single-year percentage leap. That year, deaths rose 46 percent, compared with 1917.

About 318,000 Americans and counting have been killed by COVID-19. There was cause to be optimistic about U.S. death rates before this came along.

In 2019, thanks to declines in heart disease and cancer deaths, the overall mortality rate of the nation dropped a little. And life expectancy rose for the second straight year by several weeks, according to death certificate data released by the Centers for Disease Control and Prevention on Tuesday.

However, Robert Anderson of the Centers for Disease Control and Prevention said life expectancy for 2020 could end up falling by as many as three full years.

Last year, 2,854,838 U.S. deaths were counted by the CDC or about 16,000 more than in 2018. That’s pretty good news: deaths generally rise every year by around 20,000 to 50,000, mostly because of the aging, and increasing, the population of the country.

Indeed, the age-adjusted death rate fell by about 1% in 2019, and the CDC announced that life expectancy increased by about six weeks to 78.8 years.

“Actually, as things go, it was a pretty good year for mortality,” said Anderson, who oversees CDC death statistics.

This year, both directly and indirectly, the U.S. coronavirus outbreak was a major cause of deaths.

The virus was first detected last year in China, and this year, the first U.S. cases were reported. Yet, after only cardiac disease and cancer, it has become the third leading cause of death. COVID-19 was the No. 1 killer for some parts of this year.

But certain other forms of casualties have risen as well.

COVID-19 deaths that were actually not known as such early in the outbreak may have been a burst of pneumonia cases early this year. But an unforeseen number of deaths from some types of cardiac and circulatory disorders, diabetes, and dementia have also occurred, Anderson stated.

Some of those, too, could be correlated with COVID. The virus might have weakened patients who were still dealing with these conditions, or it could have decreased the treatment they got, he said.

Some were hopeful early in the epidemic that auto crash deaths would decrease as individuals avoided traveling or driving to social events. There is still no data on that, but anecdotal accounts indicate that there was no such fall.

Compared with 2018, suicide deaths fell in 2019, but early data shows they have not continued to drop this year, Anderson and others said.

Deaths from opioid overdoses have, meanwhile, become even worse.

The U.S. was in the middle of the worst medication overdose outbreak in its history before the coronavirus had arrived.

Data is not yet available for all of 2020. But in the 12 months ending in May, the CDC announced more than 81,000 opioid overdose deaths last week, making it the highest number ever recorded in a one-year period.

Experts think a factor may have been the disruption of the pandemic to in-person care and rehabilitation facilities. Without the benefit of a friend or family member who may call 911 or administer overdose-reversing medicine, individuals are often more likely to take drugs alone.

But maybe the drugs themselves are a bigger factor: COVID-19 created supply issues for traffickers, so they are gradually mixing inexpensive and lethal fentanyl into heroin, cocaine, and methamphetamine, experts said.

I have no fear of a lot of new people unexpectedly beginning to use drugs because of COVID. If anything, I think the supply of people already using drugs is more polluted,” said Shannon Monnat, a researcher at Syracuse University who studies trends in a deaths in 2020drug overdose.”