| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 109 |
62.6%
|
| 1980 | 1 |
0.6%
|
|
| 1993 | 1 |
0.6%
|
|
| 1995 | 9 |
5.2%
|
|
| 1996 | 1 |
0.6%
|
|
| 1998 | 4 |
2.3%
|
|
| 1999 | 5 |
2.9%
|
|
| 2000 | 1 |
0.6%
|
|
| 2001 | 5 |
2.9%
|
|
| 2002 | 2 |
1.1%
|
|
| 2003 | 7 |
4%
|
|
| 2004 | 6 |
3.4%
|
|
| 2005 | 7 |
4%
|
|
| 2006 | 5 |
2.9%
|
|
| 2007 | 4 |
2.3%
|
|
| 2008 | 5 |
2.9%
|
|
| 2009 | 2 |
1.1%
|
|
| Sysmiss | 12 |