We can’t count accurately.

Estimates.

When you research war deaths the experts will quibble with each other. This Statista site has a paragraph qualifying their counts.

It was a San Francisco librarian that corrected the numbers on their 1906 earthquake deaths.

Gladys Hansen

https://www.sfgate.com/bayarea/article/Gladys-Hansen-SF-archivist-and-1906-earthquake-10994364.php