| Value | Category | Cases | |
|---|---|---|---|
| 999 | 1 |
0%
|
|
| 2000 | 2 |
0.1%
|
|
| 2001 | 41 |
1.2%
|
|
| 2002 | 244 |
7%
|
|
| 2003 | 449 |
12.9%
|
|
| 2004 | 667 |
19.2%
|
|
| 2005 | 1140 |
32.9%
|
|
| 2006 | 384 |
11.1%
|
|
| 9998 | 4 |
0.1%
|
|
| 9999 | Missing | 538 |
15.5%
|
| Sysmiss | 19042 |