| Value | Category | Cases | |
|---|---|---|---|
| 1967 | 1 |
1.4%
|
|
| 1975 | 1 |
1.4%
|
|
| 1977 | 3 |
4.1%
|
|
| 1978 | 1 |
1.4%
|
|
| 1979 | 1 |
1.4%
|
|
| 1981 | 3 |
4.1%
|
|
| 1982 | 1 |
1.4%
|
|
| 1984 | 2 |
2.7%
|
|
| 1985 | 1 |
1.4%
|
|
| 1986 | 1 |
1.4%
|
|
| 1987 | 1 |
1.4%
|
|
| 1988 | 3 |
4.1%
|
|
| 1989 | 3 |
4.1%
|
|
| 1991 | 5 |
6.8%
|
|
| 1992 | 3 |
4.1%
|
|
| 1993 | 3 |
4.1%
|
|
| 1994 | 1 |
1.4%
|
|
| 1995 | 4 |
5.4%
|
|
| 1996 | 4 |
5.4%
|
|
| 1997 | 4 |
5.4%
|
|
| 1998 | 1 |
1.4%
|
|
| 1999 | 1 |
1.4%
|
|
| 2000 | 2 |
2.7%
|
|
| 2004 | 1 |
1.4%
|
|
| 2005 | 3 |
4.1%
|
|
| 2008 | 2 |
2.7%
|
|
| 2012 | 1 |
1.4%
|
|
| 9998 | don't know | 17 |
23%
|
| Sysmiss | 16356 |