| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know | 1 |
1.6%
|
| 1965 | 1 |
1.6%
|
|
| 1974 | 1 |
1.6%
|
|
| 1978 | 2 |
3.1%
|
|
| 1985 | 2 |
3.1%
|
|
| 1987 | 2 |
3.1%
|
|
| 1988 | 1 |
1.6%
|
|
| 1991 | 1 |
1.6%
|
|
| 1992 | 3 |
4.7%
|
|
| 1993 | 2 |
3.1%
|
|
| 1995 | 2 |
3.1%
|
|
| 1997 | 2 |
3.1%
|
|
| 1998 | 6 |
9.4%
|
|
| 1999 | 2 |
3.1%
|
|
| 2000 | 11 |
17.2%
|
|
| 2001 | 2 |
3.1%
|
|
| 2002 | 2 |
3.1%
|
|
| 2003 | 3 |
4.7%
|
|
| 2004 | 3 |
4.7%
|
|
| 2005 | 2 |
3.1%
|
|
| 2006 | 1 |
1.6%
|
|
| 2007 | 4 |
6.3%
|
|
| 2008 | 5 |
7.8%
|
|
| 2010 | 1 |
1.6%
|
|
| 2012 | 2 |
3.1%
|
|
| Sysmiss | 418 |