In The Guardian Steven Pinker: fighting talk from the prophet of peace has a table of atrocities. Ranked No 1 on the naughty step is the An Lushan Rebellion, had to look that up, Tang Dynasty affair. That is Followed by the Mongols and the Arab slave trade. The famine prone Raj gets rank as 12th just pipped by Maoist China and the Brits get a dishonorable mention along with The Cousins for the Atlantic Slave trade and practically wiping out the Red Injuns. WWII gets in at 9th, WWI at 16th but we can blame the Germans for those. I'm shocked there is no mention of the Paddicaust. This a little questionable as the time spans of these events isn't really considered but China does seem to be most prone to building a pile of skulls.