I have absolutely no idea where the figures originated from,obviously some statistician with more time on his hands than is perhaps wise.
In a 24 hour period 323 million opponents are killed by players. 28 million of them are killed by head-shots. Another 2 million are stabbed in the back. 19,000 tonnes of grenades are thrown. Finally enough explosive crossbow bolts are shot by players that if they were laid end to end would cover 6,280km,which is roughly the length of The Great Wall of China.