| Value | Category | Cases | |
|---|---|---|---|
| 1994 | 4 |
0.3%
|
|
| 1995 | 22 |
1.7%
|
|
| 1996 | 144 |
11.1%
|
|
| 1997 | 266 |
20.5%
|
|
| 1998 | 323 |
24.8%
|
|
| 1999 | 404 |
31.1%
|
|
| 2000 | 137 |
10.5%
|
|
| 9997 | inconsistent | 0 |
0%
|
| 9998 | dk | 0 |
0%
|
| Sysmiss | 10936 |