| Value | Category | Cases | |
|---|---|---|---|
| 1949 | 1 |
1.5%
|
|
| 1950 | 1 |
1.5%
|
|
| 1952 | 2 |
3%
|
|
| 1957 | 2 |
3%
|
|
| 1958 | 2 |
3%
|
|
| 1959 | 1 |
1.5%
|
|
| 1961 | 1 |
1.5%
|
|
| 1962 | 2 |
3%
|
|
| 1963 | 1 |
1.5%
|
|
| 1964 | 3 |
4.5%
|
|
| 1965 | 2 |
3%
|
|
| 1966 | 2 |
3%
|
|
| 1967 | 3 |
4.5%
|
|
| 1968 | 5 |
7.6%
|
|
| 1969 | 2 |
3%
|
|
| 1970 | 1 |
1.5%
|
|
| 1971 | 6 |
9.1%
|
|
| 1972 | 2 |
3%
|
|
| 1973 | 4 |
6.1%
|
|
| 1974 | 1 |
1.5%
|
|
| 1975 | 2 |
3%
|
|
| 1976 | 2 |
3%
|
|
| 1977 | 1 |
1.5%
|
|
| 1979 | 2 |
3%
|
|
| 1980 | 2 |
3%
|
|
| 1981 | 1 |
1.5%
|
|
| 1982 | 1 |
1.5%
|
|
| 1987 | 1 |
1.5%
|
|
| 1989 | 2 |
3%
|
|
| 1991 | 1 |
1.5%
|
|
| 1997 | 1 |
1.5%
|
|
| 9999 | 9999. Don't know | 6 |
9.1%
|
| Sysmiss | 933 |