| Value | Category | Cases | |
|---|---|---|---|
| 2002 | 1 |
20%
|
|
| 2003 | 1 |
20%
|
|
| 2004 | 3 |
60%
|
|
| 9999 | 9999. Don't know | 0 |
0%
|
| Sysmiss | 994 |