| Value | Category | Cases | |
|---|---|---|---|
| 1965 | 1 |
0.1%
|
|
| 1970 | 1 |
0.1%
|
|
| 1973 | 1 |
0.1%
|
|
| 1974 | 1 |
0.1%
|
|
| 1976 | 4 |
0.5%
|
|
| 1977 | 5 |
0.6%
|
|
| 1978 | 3 |
0.3%
|
|
| 1979 | 6 |
0.7%
|
|
| 1980 | 12 |
1.4%
|
|
| 1981 | 12 |
1.4%
|
|
| 1982 | 11 |
1.3%
|
|
| 1983 | 15 |
1.7%
|
|
| 1984 | 10 |
1.2%
|
|
| 1985 | 15 |
1.7%
|
|
| 1986 | 29 |
3.3%
|
|
| 1987 | 13 |
1.5%
|
|
| 1988 | 24 |
2.8%
|
|
| 1989 | 27 |
3.1%
|
|
| 1990 | 37 |
4.3%
|
|
| 1991 | 34 |
3.9%
|
|
| 1992 | 32 |
3.7%
|
|
| 1993 | 25 |
2.9%
|
|
| 1994 | 24 |
2.8%
|
|
| 1995 | 18 |
2.1%
|
|
| 1996 | 44 |
5.1%
|
|
| 1997 | 16 |
1.8%
|
|
| 1998 | 33 |
3.8%
|
|
| 1999 | 27 |
3.1%
|
|
| 2000 | 31 |
3.6%
|
|
| 2001 | 31 |
3.6%
|
|
| 2002 | 33 |
3.8%
|
|
| 2003 | 25 |
2.9%
|
|
| 2004 | 15 |
1.7%
|
|
| 2005 | 13 |
1.5%
|
|
| 2006 | 19 |
2.2%
|
|
| 9997 | Inconsistent | 0 |
0%
|
| 9998 | DK | 219 |
25.2%
|
| 9999 | Missing | 2 |
0.2%
|
| Sysmiss | 413 |