| Value | Category | Cases | |
|---|---|---|---|
| 1968 | 1 |
0%
|
|
| 1980 | 1 |
0%
|
|
| 1981 | 1 |
0%
|
|
| 1985 | 1 |
0%
|
|
| 1988 | 2 |
0%
|
|
| 1989 | 1 |
0%
|
|
| 1990 | 6 |
0.1%
|
|
| 1992 | 2 |
0%
|
|
| 1995 | 4 |
0.1%
|
|
| 1996 | 4 |
0.1%
|
|
| 1997 | 4 |
0.1%
|
|
| 1998 | 17 |
0.3%
|
|
| 1999 | 6 |
0.1%
|
|
| 2000 | 12 |
0.2%
|
|
| 2001 | 13 |
0.3%
|
|
| 2002 | 14 |
0.3%
|
|
| 2003 | 27 |
0.5%
|
|
| 2004 | 12 |
0.2%
|
|
| 2005 | 33 |
0.7%
|
|
| 2006 | 42 |
0.8%
|
|
| 2007 | 67 |
1.3%
|
|
| 2008 | 221 |
4.4%
|
|
| 9999 | Never work | 4480 |
90.1%
|
| Sysmiss | 3016 |