| Value | Category | Cases | |
|---|---|---|---|
| 1972 | 59 |
3.5%
|
|
| 1973 | 22 |
1.3%
|
|
| 1974 | 37 |
2.2%
|
|
| 1975 | 32 |
1.9%
|
|
| 1976 | 23 |
1.3%
|
|
| 1977 | 44 |
2.6%
|
|
| 1978 | 61 |
3.6%
|
|
| 1979 | 53 |
3.1%
|
|
| 1980 | 69 |
4%
|
|
| 1981 | 65 |
3.8%
|
|
| 1982 | 111 |
6.5%
|
|
| 1983 | 137 |
8%
|
|
| 1984 | 158 |
9.2%
|
|
| 1985 | 175 |
10.2%
|
|
| 1986 | 204 |
11.9%
|
|
| 1987 | 460 |
26.9%
|