| Value | Category | Cases | |
|---|---|---|---|
| 1970 | 1 |
1.3%
|
|
| 1971 | 1 |
1.3%
|
|
| 1972 | 2 |
2.5%
|
|
| 1973 | 4 |
5.1%
|
|
| 1974 | 1 |
1.3%
|
|
| 1975 | 2 |
2.5%
|
|
| 1976 | 3 |
3.8%
|
|
| 1977 | 3 |
3.8%
|
|
| 1978 | 4 |
5.1%
|
|
| 1979 | 9 |
11.4%
|
|
| 1980 | 4 |
5.1%
|
|
| 1981 | 8 |
10.1%
|
|
| 1982 | 11 |
13.9%
|
|
| 1983 | 9 |
11.4%
|
|
| 1984 | 4 |
5.1%
|
|
| 1985 | 4 |
5.1%
|
|
| 1986 | 2 |
2.5%
|
|
| 1987 | 3 |
3.8%
|
|
| 1988 | 3 |
3.8%
|
|
| 1990 | 1 |
1.3%
|
|
| Sysmiss | 726 |