| Value | Category |
|---|---|
| 1 | 18-19 |
| 2 | 20-24 |
| 3 | 25-29 |
| 4 | 30-34 |
| 5 | 35-39 |
| 6 | 40-44 |
| 7 | 45-49 |
| 8 | 50-54 |
| 9 | 55-59 |
| 10 | 60-64 |
| 11 | 65+ |
| a | Don't know |
| b | Refused to answer |
| c | Outlier set to missing |
| d | Dropped during anonymization (available on request) |
| e | Skipped in error |
| z | Not applicable |