| Value | Category | Cases | |
|---|---|---|---|
| 99 | 99. Don't know | 0 |
0%
|
| 1980 | 3 |
8.3%
|
|
| 1981 | 5 |
13.9%
|
|
| 1982 | 6 |
16.7%
|
|
| 1983 | 5 |
13.9%
|
|
| 1984 | 6 |
16.7%
|
|
| 1985 | 3 |
8.3%
|
|
| 1986 | 3 |
8.3%
|
|
| 1987 | 3 |
8.3%
|
|
| 1988 | 2 |
5.6%
|
|
| Sysmiss | 63 |