| Value | Category | Cases | Weighted | |
|---|---|---|---|---|
| 1973 | 1 | 0 |
0.6%
|
|
| 1976 | 4 | 2 |
5.8%
|
|
| 1977 | 4 | 5 |
12.5%
|
|
| 1978 | 8 | 6 |
15.3%
|
|
| 1979 | 5 | 3 |
7.3%
|
|
| 1980 | 4 | 4 |
9.4%
|
|
| 1981 | 5 | 4 |
9.5%
|
|
| 1982 | 1 | 0 |
0.6%
|
|
| 1983 | 7 | 4 |
10.7%
|
|
| 1984 | 7 | 3 |
8.8%
|
|
| 1985 | 3 | 2 |
6.4%
|
|
| 1986 | 3 | 1 |
1.8%
|
|
| 1987 | 3 | 2 |
6.1%
|
|
| 1989 | 1 | 2 |
4.6%
|
|
| 1990 | 1 | 0 |
0.6%
|
|
| Sysmiss | 3236 | 3255 |