| Value | Category | Cases | |
|---|---|---|---|
| 1984 | 1 |
0.1%
|
|
| 1995 | 1 |
0.1%
|
|
| 1997 | 1 |
0.1%
|
|
| 1998 | 3 |
0.3%
|
|
| 1999 | 1 |
0.1%
|
|
| 2000 | 168 |
15.5%
|
|
| 2001 | 470 |
43.3%
|
|
| 2002 | 434 |
40%
|
|
| 2003 | 6 |
0.6%
|
|
| Sysmiss | 131 |