| Value | Category | Cases | |
|---|---|---|---|
| 1969 | 2 |
6.5%
|
|
| 1970 | 3 |
9.7%
|
|
| 1971 | 4 |
12.9%
|
|
| 1972 | 6 |
19.4%
|
|
| 1973 | 2 |
6.5%
|
|
| 1974 | 3 |
9.7%
|
|
| 1975 | 4 |
12.9%
|
|
| 1976 | 2 |
6.5%
|
|
| 1978 | 1 |
3.2%
|
|
| 1979 | 1 |
3.2%
|
|
| 1981 | 1 |
3.2%
|
|
| 1982 | 1 |
3.2%
|
|
| 1983 | 1 |
3.2%
|
|
| Sysmiss | 6724 |