| Value | Category | Cases | |
|---|---|---|---|
| 1 | Clinic card/vaccination booklet | 4 |
57.1%
|
| 2 | Respondent recall | 3 |
42.9%
|
| 3 | Other written source | 0 |
0%
|
| 4 | Date of birth unknown | 0 |
0%
|
| Sysmiss | 913 |