| Value | Category | Cases | |
|---|---|---|---|
| 1971 | 1 |
0.2%
|
|
| 1974 | 2 |
0.3%
|
|
| 1975 | 1 |
0.2%
|
|
| 1976 | 1 |
0.2%
|
|
| 1977 | 2 |
0.3%
|
|
| 1978 | 3 |
0.5%
|
|
| 1979 | 3 |
0.5%
|
|
| 1980 | 7 |
1.2%
|
|
| 1981 | 6 |
1%
|
|
| 1982 | 9 |
1.5%
|
|
| 1983 | 5 |
0.8%
|
|
| 1984 | 11 |
1.8%
|
|
| 1985 | 3 |
0.5%
|
|
| 1986 | 10 |
1.7%
|
|
| 1987 | 7 |
1.2%
|
|
| 1988 | 7 |
1.2%
|
|
| 1989 | 10 |
1.7%
|
|
| 1990 | 14 |
2.3%
|
|
| 1991 | 15 |
2.5%
|
|
| 1992 | 14 |
2.3%
|
|
| 1993 | 10 |
1.7%
|
|
| 1994 | 12 |
2%
|
|
| 1995 | 17 |
2.8%
|
|
| 1996 | 17 |
2.8%
|
|
| 1997 | 10 |
1.7%
|
|
| 1998 | 16 |
2.7%
|
|
| 1999 | 15 |
2.5%
|
|
| 2000 | 25 |
4.2%
|
|
| 2001 | 18 |
3%
|
|
| 2002 | 20 |
3.4%
|
|
| 2003 | 10 |
1.7%
|
|
| 2004 | 23 |
3.9%
|
|
| 2005 | 21 |
3.5%
|
|
| 2006 | 22 |
3.7%
|
|
| 2007 | 24 |
4%
|
|
| 2008 | 17 |
2.8%
|
|
| 2009 | 19 |
3.2%
|
|
| 2010 | 31 |
5.2%
|
|
| 2011 | 31 |
5.2%
|
|
| 2012 | 37 |
6.2%
|
|
| 2013 | 31 |
5.2%
|
|
| 2014 | 18 |
3%
|
|
| 9997 | Inconsistent | 0 |
0%
|
| 9998 | DK | 21 |
3.5%
|
| 9999 | Missing | 1 |
0.2%
|
| Sysmiss | 1032 |