| Value | Category | Cases | |
|---|---|---|---|
| 1972 | 1 |
0.3%
|
|
| 1973 | 1 |
0.3%
|
|
| 1974 | 1 |
0.3%
|
|
| 1978 | 1 |
0.3%
|
|
| 1979 | 1 |
0.3%
|
|
| 1980 | 4 |
1.3%
|
|
| 1981 | 1 |
0.3%
|
|
| 1982 | 2 |
0.6%
|
|
| 1983 | 11 |
3.5%
|
|
| 1984 | 9 |
2.9%
|
|
| 1985 | 2 |
0.6%
|
|
| 1986 | 5 |
1.6%
|
|
| 1987 | 8 |
2.6%
|
|
| 1988 | 7 |
2.3%
|
|
| 1989 | 10 |
3.2%
|
|
| 1990 | 15 |
4.8%
|
|
| 1991 | 8 |
2.6%
|
|
| 1992 | 12 |
3.9%
|
|
| 1993 | 13 |
4.2%
|
|
| 1994 | 20 |
6.4%
|
|
| 1995 | 29 |
9.3%
|
|
| 1996 | 19 |
6.1%
|
|
| 1997 | 26 |
8.4%
|
|
| 1998 | 34 |
10.9%
|
|
| 1999 | 38 |
12.2%
|
|
| 2000 | 26 |
8.4%
|
|
| 9997 | inconsistent | 2 |
0.6%
|
| 9998 | dk | 5 |
1.6%
|
| Sysmiss | 3678 |