Stable populations based on a life table and assumed growth rate (cont.)
Self assessment exercise
Using the same life table as on the previous page, but assuming a population growth rate of 1%, calculate the age distribution of the stable population following the method illustrated above. Use the input boxes to enter your data and click the 'Reveal answer' button to check your results.
| age group a to a+n | nLa | survivors born on average Y years ago | relative size of birth cohort born Y years ago exp{-0.01 x Y} | stable population age group a to a+n nLa x exp{-0.01 x Y} | proportion aged a to a+n in stable population |
|---|---|---|---|---|---|
| 0 – 5 | 700 | 2.5 | |||
| 5 – 10 | 500 | 7.5 | |||
| 10 – 15 | 300 | 12.5 | |||
| 15 – 20 | 200 | 17.5 | |||
| 20 – 25 | 100 | 22.5 | |||
| 25 – 30 | 0 | 27.5 | |||
| stable population total | 100.00% |
| age group a to a+n | nLa | survivors born on average Y years ago | relative size of birth cohort born Y years ago exp{-0.01 x Y} | stable population age group a to a+n nLa x exp{-0.01 x Y} | proportion aged a to a+n in stable population |
|---|---|---|---|---|---|
| 0 – 5 | 700 | 2.5 | 0.975 | 683 | 41.2% |
| 5 – 10 | 500 | 7.5 | 0.928 | 464 | 28.0% |
| 10 – 15 | 300 | 12.5 | 0.882 | 265 | 16.0% |
| 15 – 20 | 200 | 17.5 | 0.839 | 168 | 10.1% |
| 20 – 25 | 100 | 22.5 | 0.799 | 80 | 4.8% |
| 25 – 30 | 0 | 27.5 | |||
| stable population total | 1,659 | 100.00% |
Click on the following link to download the spreadsheet used to make these calculations:
Download spreadsheet 'Stationary to Stable' 
The growth rate can be altered, allowing you to see the changes in stable population age structure that result from different values of r.