I don't know but I can guarantee you it doesn't rate a 1 on the scale of 1-10 when compared to 20th century body count piled up by those (formerly) wonderful godless, atheistic, socialist, communist states. All told it is conservatively estimated that @100,000,000 people were conveniently exterminated for various reasons or no reasons at all by those icons of atheism- Stalin, Mao, Lenin, Hitler, Pol Pot, and other minor tyrants and dictators. But then I guess if you're not killed by God it doesn't really count.
I'm not sure where you are going with this. Nobody is here trying to discount the significance of senseless deaths and atrocities committed by so-called "godless" dictators. It can be argued rather successfully that historically more people have died or been murdered in the name of religion than any other cause. I doubt many people at all were killed or persecuted in the name of Athesim. Collectively, religion is guilty of more deaths than any single cause in the history of the world.