| Value | Category | Cases | |
|---|---|---|---|
| 1950 | 1 | 
                                    
                                    0.2%
                                 | |
| 1959 | 1 | 
                                    
                                    0.2%
                                 | |
| 1960 | 2 | 
                                    
                                    0.3%
                                 | |
| 1962 | 2 | 
                                    
                                    0.3%
                                 | |
| 1963 | 1 | 
                                    
                                    0.2%
                                 | |
| 1964 | 1 | 
                                    
                                    0.2%
                                 | |
| 1965 | 1 | 
                                    
                                    0.2%
                                 | |
| 1969 | 1 | 
                                    
                                    0.2%
                                 | |
| 1972 | 1 | 
                                    
                                    0.2%
                                 | |
| 1975 | 1 | 
                                    
                                    0.2%
                                 | |
| 1976 | 2 | 
                                    
                                    0.3%
                                 | |
| 1979 | 2 | 
                                    
                                    0.3%
                                 | |
| 1981 | 1 | 
                                    
                                    0.2%
                                 | |
| 1982 | 3 | 
                                    
                                    0.5%
                                 | |
| 1984 | 3 | 
                                    
                                    0.5%
                                 | |
| 1985 | 6 | 
                                    
                                    0.9%
                                 | |
| 1986 | 3 | 
                                    
                                    0.5%
                                 | |
| 1987 | 6 | 
                                    
                                    0.9%
                                 | |
| 1988 | 3 | 
                                    
                                    0.5%
                                 | |
| 1989 | 5 | 
                                    
                                    0.8%
                                 | |
| 1990 | 7 | 
                                    
                                    1.1%
                                 | |
| 1991 | 5 | 
                                    
                                    0.8%
                                 | |
| 1992 | 7 | 
                                    
                                    1.1%
                                 | |
| 1993 | 6 | 
                                    
                                    0.9%
                                 | |
| 1994 | 11 | 
                                    
                                    1.7%
                                 | |
| 1995 | 8 | 
                                    
                                    1.2%
                                 | |
| 1996 | 7 | 
                                    
                                    1.1%
                                 | |
| 1997 | 10 | 
                                    
                                    1.5%
                                 | |
| 1998 | 8 | 
                                    
                                    1.2%
                                 | |
| 1999 | 11 | 
                                    
                                    1.7%
                                 | |
| 2000 | 22 | 
                                    
                                    3.4%
                                 | |
| 2001 | 10 | 
                                    
                                    1.5%
                                 | |
| 2002 | 11 | 
                                    
                                    1.7%
                                 | |
| 2003 | 8 | 
                                    
                                    1.2%
                                 | |
| 2004 | 12 | 
                                    
                                    1.8%
                                 | |
| 2005 | 14 | 
                                    
                                    2.1%
                                 | |
| 2006 | 5 | 
                                    
                                    0.8%
                                 | |
| 2007 | 8 | 
                                    
                                    1.2%
                                 | |
| 2008 | 19 | 
                                    
                                    2.9%
                                 | |
| 2009 | 20 | 
                                    
                                    3.1%
                                 | |
| 2010 | 23 | 
                                    
                                    3.5%
                                 | |
| 2011 | 23 | 
                                    
                                    3.5%
                                 | |
| 2012 | 26 | 
                                    
                                    4%
                                 | |
| 2013 | 18 | 
                                    
                                    2.8%
                                 | |
| 2014 | 36 | 
                                    
                                    5.5%
                                 | |
| 2015 | 54 | 
                                    
                                    8.3%
                                 | |
| 2016 | 62 | 
                                    
                                    9.5%
                                 | |
| 2017 | 60 | 
                                    
                                    9.2%
                                 | |
| 3333 | Missing | 0 | 
                                    
                                    0%
                                 | 
| 5555 | Not applicable | 0 | 
                                    
                                    0%
                                 | 
| 8888 | Refused | 0 | 
                                    
                                    0%
                                 | 
| 9999 | Don't know | 95 | 
                                    
                                    14.6%
                                 | 
| Sysmiss | 1300 |