| Value | Category | Cases | |
|---|---|---|---|
| 1995 | 1 |
0.2%
|
|
| 1997 | 1 |
0.2%
|
|
| 2001 | 30 |
6.5%
|
|
| 2002 | 56 |
12%
|
|
| 2003 | 40 |
8.6%
|
|
| 2004 | 59 |
12.7%
|
|
| 2005 | 120 |
25.8%
|
|
| 2006 | 143 |
30.8%
|
|
| 2007 | 15 |
3.2%
|
|
| Sysmiss | 1 |