| Value | Category | Cases | |
|---|---|---|---|
| 1973 | 1 |
0.7%
|
|
| 1974 | 1 |
0.7%
|
|
| 1975 | 2 |
1.4%
|
|
| 1976 | 5 |
3.4%
|
|
| 1977 | 2 |
1.4%
|
|
| 1978 | 8 |
5.4%
|
|
| 1979 | 10 |
6.8%
|
|
| 1980 | 5 |
3.4%
|
|
| 1981 | 6 |
4.1%
|
|
| 1982 | 14 |
9.5%
|
|
| 1983 | 10 |
6.8%
|
|
| 1984 | 20 |
13.5%
|
|
| 1985 | 16 |
10.8%
|
|
| 1986 | 7 |
4.7%
|
|
| 1987 | 9 |
6.1%
|
|
| 1988 | 5 |
3.4%
|
|
| 1989 | 7 |
4.7%
|
|
| 1990 | 9 |
6.1%
|
|
| 1991 | 4 |
2.7%
|
|
| 1992 | 6 |
4.1%
|
|
| 1993 | 1 |
0.7%
|
|
| Sysmiss | 8296 |