| Value | Category | Cases | |
|---|---|---|---|
| -9 | don't know | 17 |
3.7%
|
| -8 | does not apply | 0 |
0%
|
| -7 | refused to answer | 0 |
0%
|
| 1990 | 1 |
0.2%
|
|
| 1994 | 1 |
0.2%
|
|
| 2000 | 4 |
0.9%
|
|
| 2001 | 3 |
0.7%
|
|
| 2002 | 3 |
0.7%
|
|
| 2003 | 2 |
0.4%
|
|
| 2004 | 6 |
1.3%
|
|
| 2005 | 13 |
2.8%
|
|
| 2006 | 38 |
8.3%
|
|
| 2007 | 95 |
20.7%
|
|
| 2008 | 275 |
60%
|
|
| Sysmiss | 298 |