| Value | Category | Cases | |
|---|---|---|---|
| 1991 | 1 |
2.5%
|
|
| 1992 | 2 |
5%
|
|
| 1993 | 3 |
7.5%
|
|
| 1994 | 2 |
5%
|
|
| 1995 | 7 |
17.5%
|
|
| 1996 | 7 |
17.5%
|
|
| 1997 | 1 |
2.5%
|
|
| 1998 | 4 |
10%
|
|
| 1999 | 3 |
7.5%
|
|
| 2000 | 3 |
7.5%
|
|
| 2001 | 3 |
7.5%
|
|
| 2002 | 1 |
2.5%
|
|
| 2005 | 1 |
2.5%
|
|
| 2010 | 1 |
2.5%
|
|
| 2011 | 1 |
2.5%
|
|
| 9998 | Don't know | 0 |
0%
|
| Sysmiss | 41972 |