| Value | Category | Cases | |
|---|---|---|---|
| 1974 | 3 |
4.1%
|
|
| 1975 | 1 |
1.4%
|
|
| 1976 | 4 |
5.5%
|
|
| 1977 | 2 |
2.7%
|
|
| 1978 | 3 |
4.1%
|
|
| 1979 | 1 |
1.4%
|
|
| 1980 | 7 |
9.6%
|
|
| 1981 | 8 |
11%
|
|
| 1982 | 9 |
12.3%
|
|
| 1983 | 8 |
11%
|
|
| 1984 | 3 |
4.1%
|
|
| 1985 | 4 |
5.5%
|
|
| 1986 | 6 |
8.2%
|
|
| 1987 | 3 |
4.1%
|
|
| 1988 | 5 |
6.8%
|
|
| 1989 | 2 |
2.7%
|
|
| 1990 | 2 |
2.7%
|
|
| 1991 | 2 |
2.7%
|
|
| Sysmiss | 8371 |