Plot twist: They're already zombies

what about the ones who wander in from canada.
or there are also kids and babies who cannot kill

Then you integrate the human on human massacres, making it a lower number within itself, so less human = less zombies killed, and the periods of no violence. Also factor in the humans that turn during that time period of a year.

Assuming babies are going to be born, that just adds to the population. And if more humans are turned into zombies, that not only decreases the population able to kill zombies, but also increases the amount of zombies the remaining people have to kill.

This is awesome.

as I know, zombies are walking dead, therefore subject to normal decay as with unwalking dead. They should freeze during the winter and decompose in the summer. jmo

This is some good math

Im trying to remember the lyrics of this song:
Let's come together in this world
Like a
Unibrow on an Indian girl
And now let's DANCE DANCE DANCE DA-DA DANCE TO THESE STEREOTYPES
I love those fat Americans
Aren't they so obnoxious?
Always eating burgers
And always holding shotguns
(I think it's called The Stereotypes Song?Please help! :)
(I am not making fun of Americans, as I am an American.)