| Value | Category | Cases | |
|---|---|---|---|
| 0 | IF NEVER, | 3984 |
88.1%
|
| 98 | IF DON'T KNOW, | 78 |
1.7%
|
| 1970 | 2 |
0%
|
|
| 1974 | 1 |
0%
|
|
| 1988 | 2 |
0%
|
|
| 1989 | 2 |
0%
|
|
| 1990 | 1 |
0%
|
|
| 1996 | 2 |
0%
|
|
| 1997 | 1 |
0%
|
|
| 1998 | 4 |
0.1%
|
|
| 1999 | 4 |
0.1%
|
|
| 2000 | 1 |
0%
|
|
| 2001 | 8 |
0.2%
|
|
| 2002 | 12 |
0.3%
|
|
| 2003 | 18 |
0.4%
|
|
| 2004 | 32 |
0.7%
|
|
| 2005 | 61 |
1.3%
|
|
| 2006 | 157 |
3.5%
|
|
| 2007 | 140 |
3.1%
|
|
| 2008 | 6 |
0.1%
|
|
| 2009 | 5 |
0.1%
|
|
| Sysmiss | 605 |