Sometimes the number game just doesn't add up. A conversation over at 4chan led BuzzFeed to hand over some helpful illustrations about the Walking Dead universe... and why that little “zombie problem” of theirs should really be over by now.
So, from what we know about population, there are 300 million people in the U.S. If even 99% of the population is infected, there are still three million regular old people around. And if they split off into groups like Rick's (which many will have to do to survive), then they rack up a steady kill count.
...and by that count, the zombies should all be dead within a year or so.
What do you think? Even bringing neighboring countries into account, it still seems likely that they would have finished this up a while ago. You can check out BuzzFeed for the exact breakdown and more helpful image aids!