Value | Category |
---|---|
-9 | Don't know (spontaneous) |
1960 | |
1965 | |
1967 | |
1970 | |
1972 | |
1976 | |
1977 | |
1978 | |
1980 | |
1982 | |
1983 | |
1984 | |
1985 | |
1986 | |
1987 | |
1988 | |
1990 | |
1991 | |
1992 | |
1993 | |
1994 | |
1995 | |
1996 | |
1997 | |
1998 | |
1999 | |
2000 | |
2001 | |
2002 | |
2003 | |
2004 | |
2005 | |
2006 | |
2007 | |
2008 | |
2009 | |
2010 | |
2011 | |
2012 | |
2013 | |
2014 | |
2015 | |
2016 | |
NA |