| Value | Category |
|---|---|
| 1 | Last 1 month |
| 2 | 1-3 months |
| 3 | 4-6 months |
| 4 | 7-12 months |
| 5 | More than 12 months |
| 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 administered in this wave |
| z | Not applicable |