In the U.S., deaths were 16%-17% higher than expected. The death rate was 17.8% higher than in 2019. Excess deaths were higher in 1918, but every other year since 1900 is lower.
Using 1946-2019 as our sample, the average yearly change in death rate is -0.2% with a standard deviation of about 1.47 (percentage points). The biggest increase in this year range was 3.1% (2.2σ).
If we go back before the antibiotic era, the biggest one-year increases are in 1918 (29.3%) and 1929 (7.2%). Note that statistics before 1933 don't include all states.
For some other ways of looking at the data, here's an economists blog post: https://economistwritingeveryday.com/2021/01/06/excess-morta...
(He was writing in January, so had less complete stats.)
The pre-war population of this country was around 34mln - a figure reached again in the early 70s - while currently it's slightly less than 38mln, so this event can definitely be seen as rare.
One factor to bear in mind is the 5 year period includes a particularly nasty flu season in 2017-18 so the last 5 year period includes a high outlier.
The thing is over the long term all kinds of outlier events pop up, like this one, but it's hard to think of any with this magnitude. 9/11 killed 3k people in one go, but that's only one tenth of the excess deaths in New York from Covid in a single month. Even the 1906 Earthquake that devastated San Francisco only killed less than 1% of the city's population. World War 2 had an appreciable effect of course at 300k deaths over about 3 years.
If we're including other pandemics of course there's the Spanish Flu which also killed about half a million Americans or more, against a population a third the size.