expansive, concave Sides, high birth rate, high death rate, short life expectancy, rapid fall in each upward age group due to high death range
expansive, straight sides, still high birth rate, falling death rate, slightly longer life expectancy, fall in death range so more people living into middle age
stationary, convex sides, declining birth rate, low death rate, long life expectancy, an increasing proportion of the population is 65+
contractive, convex side, very low birth rate, low death rate, longer life expectancy, higher dependency ratio