| Value | Category | Cases | |
|---|---|---|---|
| 1972 | 1 |
0%
|
|
| 1989 | 1 |
0%
|
|
| 1990 | 1 |
0%
|
|
| 1991 | 1 |
0%
|
|
| 1992 | 1 |
0%
|
|
| 1993 | 2 |
0%
|
|
| 1994 | 1 |
0%
|
|
| 1995 | 1 |
0%
|
|
| 1996 | 2 |
0%
|
|
| 1997 | 2 |
0%
|
|
| 1998 | 3 |
0%
|
|
| 1999 | 3 |
0%
|
|
| 2000 | 121 |
0.7%
|
|
| 2001 | 55 |
0.3%
|
|
| 2002 | 75 |
0.4%
|
|
| 2003 | 82 |
0.5%
|
|
| 2004 | 129 |
0.7%
|
|
| 2005 | 191 |
1.1%
|
|
| 2006 | 196 |
1.1%
|
|
| 2007 | 302 |
1.7%
|
|
| 2008 | 627 |
3.6%
|
|
| 2009 | 998 |
5.7%
|
|
| 2010 | 937 |
5.3%
|
|
| 2011 | 20 |
0.1%
|
|
| 2222 | Not asked in phase 2 | 732 |
4.2%
|
| 3333 | Missing | 12 |
0.1%
|
| 5555 | Can't remember | 1758 |
10%
|
| 7777 | Never | 10895 |
61.8%
|
| 8888 | Refused | 41 |
0.2%
|
| 9999 | Don't know | 436 |
2.5%
|
| Sysmiss | 4248 |