| Value | Category | Cases | |
|---|---|---|---|
| 99 | Mising | 0 |
0%
|
| 1994 | 1 |
20%
|
|
| 2005 | 1 |
20%
|
|
| 2007 | 1 |
20%
|
|
| 2009 | 1 |
20%
|
|
| 2012 | 1 |
20%
|
|
| Sysmiss | 1720 |