| Value | Category | Cases | |
|---|---|---|---|
| 1 | Clinic card/vaccination booklet | 43 |
39.4%
|
| 2 | Respondent recall | 61 |
56%
|
| 3 | Other written source | 2 |
1.8%
|
| 4 | Date of birth unknown | 3 |
2.8%
|
| Sysmiss | 811 |