| Value | Category | Cases | Weighted | |
|---|---|---|---|---|
| 1973 | 2 | 3 |
44.5%
|
|
| 1976 | 1 | 1 |
16.2%
|
|
| 1979 | 1 | 1 |
16.2%
|
|
| 1980 | 1 | 1 |
13.8%
|
|
| 1981 | 2 | 0 |
6.3%
|
|
| 1985 | 1 | 0 |
3.1%
|
|
| Sysmiss | 3285 | 3286 |