There are books on it. Just quick search found sources. Believe to narrow down w...

There are books on it. Just quick search found sources. Believe to narrow down what is meant by violence , it is all violent deaths, by war or murder.

https://www.scientificamerican.com/article/history-and-the-d...

https://stevenpinker.com/publications/better-angels-our-natu...

https://fivebooks.com/best-books/decline-violence-steven-pin...