| Value | Category | Cases | |
|---|---|---|---|
| 1988 | 8 |
0.4%
|
|
| 1989 | 5 |
0.2%
|
|
| 1993 | 4 |
0.2%
|
|
| 1995 | 21 |
0.9%
|
|
| 1996 | 12 |
0.5%
|
|
| 1997 | 13 |
0.6%
|
|
| 1998 | 23 |
1%
|
|
| 1999 | 8 |
0.4%
|
|
| 2000 | 59 |
2.6%
|
|
| 2001 | 61 |
2.7%
|
|
| 2002 | 121 |
5.4%
|
|
| 2003 | 288 |
12.9%
|
|
| 2004 | 443 |
19.8%
|
|
| 2005 | 388 |
17.3%
|
|
| 2006 | 321 |
14.3%
|
|
| 9997 | Inconsistent | 0 |
0%
|
| 9998 | DK | 438 |
19.6%
|
| 9999 | Missing | 25 |
1.1%
|
| Sysmiss | 39568 |