| Value | Category | Cases | |
|---|---|---|---|
| 1 | Clinic card/vaccination booklet | 508 |
55.2%
|
| 2 | Respondent recall | 378 |
41.1%
|
| 3 | Other written source | 19 |
2.1%
|
| 4 | Date of birth unknown | 15 |
1.6%
|