Considering Left 4 Dead 2 has been out for only two months, its astounding that the community has managed to kill 28 Billion Zombies. Here are the stats:

[Via Left4Dead 2 Blog]

In the first two months of Left 4 Dead 2′s release, 28,981,249,043 zombies have been shot, bludgeoned, chainsawed and killed — or, for our younger readers, taken to a farm where they can frolic and shuffle around forever.
You read that correctly: 28 BILLION. To put that number in perspective:

• The entire population of the planet has been zombified and killed 4.26 times.
• With the average height of a zombie being 6 feet, if you stacked them end to end they would circle the globe 1,322 times.