| Value | Category | Cases | |
|---|---|---|---|
| 0 | Preprinted 'X' | 4235 |
9.5%
|
| 1 | 2003 | 1667 |
3.7%
|
| 2 | 2002 | 1244 |
2.8%
|
| 3 | 2001 | 911 |
2%
|
| 4 | 2000 | 326 |
0.7%
|
| 5 | Before 2000 | 479 |
1.1%
|
| 6 | Not vaccinated | 35882 |
80.2%
|
| Sysmiss | 7157 |