So Much Popcorn

How do they fit all that popcorn in one bag? I'm not talking about putting little kernels in and then making them expand. I'm always surprised by how many popped kernels come out of the bag. I see the size of it when I pull it out of the microwave, then I empty some out. It seems like there's usually at least 123% of the amount I thought there was. Does this happen to anyone else?