| Value | Category | Cases | |
|---|---|---|---|
| 1957 | 6 |
1.6%
|
|
| 1958 | 4 |
1.1%
|
|
| 1959 | 7 |
1.9%
|
|
| 1960 | 4 |
1.1%
|
|
| 1961 | 6 |
1.6%
|
|
| 1962 | 3 |
0.8%
|
|
| 1963 | 10 |
2.7%
|
|
| 1964 | 10 |
2.7%
|
|
| 1965 | 8 |
2.2%
|
|
| 1966 | 8 |
2.2%
|
|
| 1967 | 14 |
3.8%
|
|
| 1968 | 5 |
1.4%
|
|
| 1969 | 8 |
2.2%
|
|
| 1970 | 11 |
3%
|
|
| 1971 | 18 |
4.9%
|
|
| 1972 | 4 |
1.1%
|
|
| 1973 | 13 |
3.6%
|
|
| 1974 | 8 |
2.2%
|
|
| 1975 | 12 |
3.3%
|
|
| 1976 | 17 |
4.6%
|
|
| 1977 | 9 |
2.5%
|
|
| 1978 | 11 |
3%
|
|
| 1979 | 6 |
1.6%
|
|
| 1980 | 16 |
4.4%
|
|
| 1981 | 13 |
3.6%
|
|
| 1982 | 12 |
3.3%
|
|
| 1983 | 7 |
1.9%
|
|
| 1984 | 8 |
2.2%
|
|
| 1985 | 18 |
4.9%
|
|
| 1986 | 12 |
3.3%
|
|
| 1987 | 14 |
3.8%
|
|
| 1988 | 23 |
6.3%
|
|
| 1989 | 19 |
5.2%
|
|
| 1990 | 21 |
5.7%
|
|
| 1991 | 1 |
0.3%
|
|
| 9997 | Inconsistent | 0 | |
| 9998 | DK | 2 | |
| 9999 | Missing | 0 | |
| Sysmiss | 16 |