| Value | Category | Cases | |
|---|---|---|---|
| 1978 | 1 |
1.8%
|
|
| 1981 | 1 |
1.8%
|
|
| 1986 | 2 |
3.5%
|
|
| 1989 | 1 |
1.8%
|
|
| 1990 | 2 |
3.5%
|
|
| 1992 | 1 |
1.8%
|
|
| 1995 | 2 |
3.5%
|
|
| 1996 | 2 |
3.5%
|
|
| 1998 | 1 |
1.8%
|
|
| 2000 | 2 |
3.5%
|
|
| 2001 | 3 |
5.3%
|
|
| 2002 | 1 |
1.8%
|
|
| 2004 | 2 |
3.5%
|
|
| 2005 | 6 |
10.5%
|
|
| 2006 | 1 |
1.8%
|
|
| 2007 | 8 |
14%
|
|
| 2008 | 1 |
1.8%
|
|
| 9999 | Do not know | 20 |
35.1%
|
| Sysmiss | 2779 |