| Value | Category | Cases | |
|---|---|---|---|
| -2 | Refusal to answer | 1 |
0.1%
|
| -1 | Don't know | 7 |
0.5%
|
| 1900 | 1 |
0.1%
|
|
| 1968 | 1 |
0.1%
|
|
| 1970 | 2 |
0.1%
|
|
| 1974 | 1 |
0.1%
|
|
| 1975 | 1 |
0.1%
|
|
| 1978 | 1 |
0.1%
|
|
| 1980 | 6 |
0.4%
|
|
| 1981 | 1 |
0.1%
|
|
| 1982 | 1 |
0.1%
|
|
| 1985 | 6 |
0.4%
|
|
| 1986 | 3 |
0.2%
|
|
| 1987 | 5 |
0.3%
|
|
| 1988 | 11 |
0.7%
|
|
| 1989 | 17 |
1.1%
|
|
| 1990 | 54 |
3.6%
|
|
| 1991 | 62 |
4.1%
|
|
| 1992 | 62 |
4.1%
|
|
| 1993 | 37 |
2.5%
|
|
| 1994 | 84 |
5.6%
|
|
| 1995 | 108 |
7.2%
|
|
| 1996 | 93 |
6.2%
|
|
| 1997 | 92 |
6.1%
|
|
| 1998 | 194 |
12.9%
|
|
| 1999 | 190 |
12.7%
|
|
| 2000 | 366 |
24.4%
|
|
| 2001 | 93 |
6.2%
|
|
| Sysmiss | 65 |