| Value | Category | Cases | |
|---|---|---|---|
| 0 | 458 |
95.8%
|
|
| 1970 | 1 |
0.2%
|
|
| 1995 | 1 |
0.2%
|
|
| 1998 | 1 |
0.2%
|
|
| 2000 | 2 |
0.4%
|
|
| 2005 | 3 |
0.6%
|
|
| 2007 | 1 |
0.2%
|
|
| 2008 | 1 |
0.2%
|
|
| 2009 | 1 |
0.2%
|
|
| 2010 | 9 |
1.9%
|
|
| Sysmiss | 2 |