expansive: birth rate
broad base = high birth rate
expansive: rate of growth
high population growth
expansive: rate of death
narrow top = high death rate
stable: birth rate
narrow base = low birth rate
stable: rate of growth
stable population growth (little/no growth)
stable: rate of death
narrow top = low death rate
declining: birth rate
narrow base = low birth rate
declining: rate of death
broad top = low death rate
declining: rate of growth
declining population