Proportions
Proportions show the size of a sub-group of the population relative to the total population. They are calculated by dividing the number within the sub-group of interest by the total population:
| Proportion = | Pi |
| P |
where
- Pi is the sub-group of interest and P is the total population.
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to see an example.
In Argentina in 2010 the total population (000s) was 40,412. Of these, 3386 were aged under 5, or 0-4 years. We can calculate the proportion of the population aged 0-4 in 2010 as:
| Proportion aged 0 – 4 = | 3386 | = 0.08 |
| 40412 |
The proportion of the population aged 0-4 years is 0.08. In order to calculate the percentage of the population aged 0-4, we simply multiply this value by 100 to get 8%. As you can see, the numerator (all those aged 0-4) is included in the denominator (all those aged 0-4 +all those above the age of 4).
A proportion will always be between 0 and 1. However, we can express it as a percentage by multiplying the value by 100, or per 1000 by multiplying by 1000 and so on.
Note: The subscript i is used to denote a subgroup of the population.