How many rounds are in black ops 2 zombies?

The number of rounds is unlimited. You keep going until you die. There are only three different maps though. Treyarch will probably release new maps/dlcs on xbox live and psn in the coming months, considering how much $ they have already made off the game. While this stands me and my friend realized that at aproximately round 147 most guns do almost no harm unless getting perfect headshots.