| Value | Category | Cases | |
|---|---|---|---|
| -2 | don't know | 102 |
33.7%
|
| 1959 | 1 |
0.3%
|
|
| 1960 | 1 |
0.3%
|
|
| 1967 | 1 |
0.3%
|
|
| 1969 | 1 |
0.3%
|
|
| 1970 | 4 |
1.3%
|
|
| 1974 | 1 |
0.3%
|
|
| 1975 | 5 |
1.7%
|
|
| 1978 | 1 |
0.3%
|
|
| 1979 | 2 |
0.7%
|
|
| 1980 | 9 |
3%
|
|
| 1981 | 1 |
0.3%
|
|
| 1982 | 3 |
1%
|
|
| 1983 | 2 |
0.7%
|
|
| 1984 | 4 |
1.3%
|
|
| 1985 | 14 |
4.6%
|
|
| 1986 | 8 |
2.6%
|
|
| 1987 | 11 |
3.6%
|
|
| 1988 | 12 |
4%
|
|
| 1989 | 12 |
4%
|
|
| 1990 | 14 |
4.6%
|
|
| 1991 | 6 |
2%
|
|
| 1992 | 5 |
1.7%
|
|
| 1993 | 4 |
1.3%
|
|
| 1994 | 2 |
0.7%
|
|
| 1995 | 4 |
1.3%
|
|
| 1996 | 5 |
1.7%
|
|
| 1997 | 7 |
2.3%
|
|
| 1998 | 9 |
3%
|
|
| 1999 | 8 |
2.6%
|
|
| 2000 | 9 |
3%
|
|
| 2001 | 1 |
0.3%
|
|
| 2002 | 5 |
1.7%
|
|
| 2003 | 2 |
0.7%
|
|
| 2004 | 1 |
0.3%
|
|
| 2005 | 2 |
0.7%
|
|
| 2006 | 2 |
0.7%
|
|
| 2007 | 7 |
2.3%
|
|
| 2008 | 6 |
2%
|
|
| 2009 | 9 |
3%
|
|
| Sysmiss | 746 |