| Value | Category |
|---|---|
| 0 | no data from individual questionnaire |
| 1 | Age and sex the same |
| 2 | Age same, sex different |
| 3 | Age < 5 years different, sex the same |
| 4 | Age < 5 years different, sex different |
| 5 | Age 5+ years different, sex the same |
| 6 | Age 5+ years different, sex different |
| 8 | None, all imputed |
| Sysmiss |