| Value | Category | Cases | |
|---|---|---|---|
| 2002 | 1 |
1.4%
|
|
| 2006 | 1 |
1.4%
|
|
| 2007 | 31 |
44.9%
|
|
| 2008 | 36 |
52.2%
|
|
| Sysmiss | 3216 |