For the fourteenth year running, Japan's population has slumped to a record low. The non-foreign population dropped by nearly 900,000 — an unprecedented fall.
People are always born with the same age namely 0, but they do not all die at the same age. In fact getting older increases chances of death. Hence 2 babies per mother ends up in a pyramid too.
Even if you presume people all die at the same age, things will be stable. If say people all get childten at 30 and only work between 30-60 and then all die at 90. If we then assume 1 child per couple and everybody has a child at 30, we would get a stable dependency ratio of 2.5 dependents per worker. Obviously those numbers are not realistic. Btw that also is not a pyramid, but a trapezoid.
People are always born with the same age namely 0, but they do not all die at the same age. In fact getting older increases chances of death. Hence 2 babies per mother ends up in a pyramid too.
Even if you presume people all die at the same age, things will be stable. If say people all get childten at 30 and only work between 30-60 and then all die at 90. If we then assume 1 child per couple and everybody has a child at 30, we would get a stable dependency ratio of 2.5 dependents per worker. Obviously those numbers are not realistic. Btw that also is not a pyramid, but a trapezoid.