You would get the impression that WTS claims about the huge upsurge in deadly wars from the time of WWI onward primarily refer to the wars that took place in Europe.
Other posters on this thread, though, have drawn attention to the massive death toll of (earlier) wars that were fought in Asia.
Even in Europe, large scale warfare has run in cycles:
eg: - The Thirty Years War of the 17th Century (any war that kills 75% of a country's population has to be treated as a large-scale one!)
- The Napoleonic Wars of the first decade of the 19th Century.
Concerning the last 100 years, would it not be correct to say that the 61 years since the end of WWII is one of the longest periods of stability that Europe has known?
Perhaps W. Schnell, in his "Thirty Years a Watchtower Slave", had a point:
He maintained (when discussing this thought of "more and more deadly wars") that the WTS merely capitalised on the great upheaval in Europe that followed the First World War.
- After all, they had to do something to detract from the fact that they were completely wrong about 1914!