1. Population Pyramids Ratios and Statistics

2. Dependency Ratio A measure of the portion of a population which is composed of dependents (people who are too young or too old to work). The dependency ratio is equal to the number of individuals aged below 15 or above 64 divided by the number of individuals aged 15 to 64, expressed as a percentage. A rising dependency ratio is a concern in many countries that are facing an aging population, since it becomes difficult for pension and social security systems to provide for a significantly older, non-working population.

3. Rate of Natural Increase Birth rate (b) − death rate (d) = rate of natural increase (r). birth rate expressed as number of births per 1000 per year (currently 14 in the U.S.) death rate expressed as the number of deaths per 1000 per year (currently 8 in the U.S.) So the rate of natural increase is 6 per thousand Must be represented as a percentage. (Out of 100)

4. Rate of Natural Increase - Formula RNI = Birth Rate – Death Rate 10 Example: USA - birth rate 14 / 1000 per year death rate 8 / 1000 per year Calculate the RNI?

5. Rate of Natural Increase - Formula Answer: RNI = Birth Rate – Death Rate 10 RNI = 14 – 8 10 RNI = 6= 0.6 % 10

6. Doubling Time Doubling Time = 70 RNI The US has an RNI of 0.6%, therefore at this rate the US population will double in? DT = 70= 116 years 0.6