| Value | Category | Cases | |
|---|---|---|---|
| 0 | 323 |
67.6%
|
|
| 1980 | 2 |
0.4%
|
|
| 1987 | 1 |
0.2%
|
|
| 1990 | 1 |
0.2%
|
|
| 1995 | 2 |
0.4%
|
|
| 1996 | 2 |
0.4%
|
|
| 1998 | 7 |
1.5%
|
|
| 2000 | 9 |
1.9%
|
|
| 2001 | 2 |
0.4%
|
|
| 2002 | 2 |
0.4%
|
|
| 2004 | 8 |
1.7%
|
|
| 2005 | 9 |
1.9%
|
|
| 2006 | 9 |
1.9%
|
|
| 2007 | 16 |
3.3%
|
|
| 2008 | 21 |
4.4%
|
|
| 2009 | 15 |
3.1%
|
|
| 2010 | 49 |
10.3%
|
|
| Sysmiss | 2 |