New data is showing that 2021 ended up being the deadliest year in U.S. history and new research is offering more insights into how it got that bad.

The C.D.C. reported that there were 3.465 million deaths last year, or about 80,000 more than 2020's record setting total.

The main reason for the jump? COVID-19. That's despite early optimism that 2021 would not be as bad partly because effective COVID-19 vaccines had finally become available, though experts say the hesitancy around the shots and refusals to follow precautions kept boosting the numbers.

But the coronavirus is not solely to blame. Preliminary data also shows the death rate for cancer rose slightly and rates continued to increase for diabetes, chronic liver disease and stroke.

Drug overdose deaths also continued to rise especially among 14- to 18-year-olds.