Is There an Exponential Growth in Universes?

We don't even know if the number is finite or infinite. It's certainly a large number because literally every time a tiny quantum mechanical system that is in a superposition becomes entangled with the rest of the world, the world branches into multiple possibilities. These quantum entanglements are quite common events. In a typical human body, a radioactive decay happens about 5,000 times per second. And there's a lot of bodies out there.