| Value | Category | Cases | |
|---|---|---|---|
| 1968 | 1 |
0.1%
|
|
| 1980 | 1 |
0.1%
|
|
| 1981 | 1 |
0.1%
|
|
| 1982 | 1 |
0.1%
|
|
| 1984 | 1 |
0.1%
|
|
| 1985 | 1 |
0.1%
|
|
| 1986 | 2 |
0.2%
|
|
| 1991 | 3 |
0.4%
|
|
| 1992 | 4 |
0.5%
|
|
| 1993 | 1 |
0.1%
|
|
| 1994 | 6 |
0.7%
|
|
| 1995 | 6 |
0.7%
|
|
| 1996 | 13 |
1.6%
|
|
| 1997 | 17 |
2%
|
|
| 1998 | 26 |
3.1%
|
|
| 1999 | 28 |
3.4%
|
|
| 2000 | 38 |
4.6%
|
|
| 2001 | 36 |
4.3%
|
|
| 2002 | 65 |
7.8%
|
|
| 2003 | 71 |
8.5%
|
|
| 2004 | 83 |
10%
|
|
| 2005 | 141 |
16.9%
|
|
| 2006 | 267 |
32.1%
|
|
| 2007 | 14 |
1.7%
|
|
| 9997 | Inconsistent | 0 |
0%
|
| 9998 | DK | 5 |
0.6%
|
| 9999 | Missing | 0 |
0%
|
| Sysmiss | 449 |