| Value | Category | Cases | |
|---|---|---|---|
| -2 | Refusal to answer | 0 |
0%
|
| -1 | Don't know | 1 |
1.6%
|
| 1981 | 1 |
1.6%
|
|
| 1989 | 1 |
1.6%
|
|
| 1990 | 6 |
9.5%
|
|
| 1991 | 1 |
1.6%
|
|
| 1992 | 2 |
3.2%
|
|
| 1993 | 1 |
1.6%
|
|
| 1994 | 2 |
3.2%
|
|
| 1995 | 2 |
3.2%
|
|
| 1996 | 4 |
6.3%
|
|
| 1997 | 5 |
7.9%
|
|
| 1998 | 6 |
9.5%
|
|
| 1999 | 9 |
14.3%
|
|
| 2000 | 13 |
20.6%
|
|
| 2001 | 9 |
14.3%
|
|
| Sysmiss | 7786 |