| Value | Category | Cases | |
|---|---|---|---|
| 1964 | 1 |
1.4%
|
|
| 1966 | 2 |
2.8%
|
|
| 1968 | 1 |
1.4%
|
|
| 1969 | 1 |
1.4%
|
|
| 1970 | 5 |
7%
|
|
| 1972 | 8 |
11.3%
|
|
| 1973 | 7 |
9.9%
|
|
| 1974 | 11 |
15.5%
|
|
| 1975 | 5 |
7%
|
|
| 1976 | 7 |
9.9%
|
|
| 1977 | 4 |
5.6%
|
|
| 1978 | 4 |
5.6%
|
|
| 1979 | 4 |
5.6%
|
|
| 1980 | 5 |
7%
|
|
| 1982 | 2 |
2.8%
|
|
| 1983 | 1 |
1.4%
|
|
| 1984 | 3 |
4.2%
|
|
| Sysmiss | 6684 |