| Value | Category |
|---|---|
| -98 | Don't Know |
| -97 | Declined |
| 1 | Less than 15 |
| 2 | 15-19 |
| 3 | 20-24 |
| 4 | 25-29 |
| 5 | 30-34 |
| 6 | 35+ |
| a | Don't know |
| b | Refused to answer |
| c | Outlier set to missing |
| d | Dropped during anonymization (available on request) |
| e | Skipped in error |
| m | Not available in wave |
| z | Not applicable |