1. Introduction to Population Pyramids

2. Dependency Ratio
The number of people who are too young or too old to work, compared to the number of people in their productive years

3. Dependency Ratio 0-14 = Dependents 15-64 = Workers 64+ = Dependents
DR = Number of Dependents (0-15 and 65+)
Number of Working-age (16-64)
X 100

4. Population under the age of 15 - usually shown as a percentage of the total population of a country - dependency age is 0-15

5. Sex Ratio Sex Ratio: number of males per hundred females
In general more males are born than females
Males have higher death rates
Examples:
Europe and North America = 95:100
Rest of World = 102:100

6. Sex Ratio – Developing Countries
Have large % of young people –where males generally outnumber females
Lower % of older people – where females are typically more numerous
High immigration = more males

7. Population Pyramids
A country’s stage in Demographic Transition gives it a distinctive population structure
Also called
Age-Sex Pyramids

8. THE POWER OF THE PYRAMID
- A POPULATION PYRAMID is a graphic device that allows Demographers to look at how events affect populations of countries.
- What are the ages of the people?
- How many are men?
- How many are women?
- Graphs show a breakdown of a country’s population and how economic, political, and natural events over 70 – 80 years can impact different age groups. The graphs can help predict future population tends.

9. Population Pyramids –
Graphs that show the percentages of each age group in the total population, divided by gender.
For poorer countries, the chart is shaped like a pyramid. Infant mortality rates are high, life expectancy is shorter.

10. Examples of population pyramids and their meaning

11. A typical example of a high birth rate and high death rate pyramid
A typical example of a high birth rate and high death rate pyramid. Life expectancy is low.

12. An even more extreme example of high birth and death rates.

13. China’s pyramid shows the results of the single child policy.

14. The US pyramid shows the results of the baby boom ( ) and maybe the “baby bounce” years later

15. Population Pyramid Population composition on graph:
Males = left side of the vertical axis
Females = right side of the vertical axis
Age = order sequentially with youngest
at the bottom and oldest at the top
(usually by five-year cohorts)

16. Rapid Growth A country in stage 2 of the Demographic Transition Model
Large number of young people and a smaller older population

17. Slow Growth A country in stage 4 of the Demographic Transition Model
Large number of “older people”
Smaller % of young people

18. No Growth End of stage 4, entering Stage 5
Large number of “older people”
Very small % of young people

19. What stage goes with each pyramid?
Developing Relatively Developed Developed
(poor) (rich)
What stage goes with each pyramid?

22. National Scale