| Value | Category | Cases | |
|---|---|---|---|
| 1 | Full date known | 7 |
2.8%
|
| 2 | Day unknown | 11 |
4.5%
|
| 4 | Day and month unknown | 57 |
23.1%
|
| 8 | Unknown | 172 |
69.6%
|
| 9 | Missing | 0 | |
| Sysmiss | 694 |