| Value | Category | Cases | |
|---|---|---|---|
| 1980 | 1 | 
                                    
                                    0%
                                 | |
| 1985 | 2 | 
                                    
                                    0.1%
                                 | |
| 1986 | 2 | 
                                    
                                    0.1%
                                 | |
| 1987 | 6 | 
                                    
                                    0.3%
                                 | |
| 1988 | 3 | 
                                    
                                    0.1%
                                 | |
| 1989 | 17 | 
                                    
                                    0.8%
                                 | |
| 1990 | 10 | 
                                    
                                    0.5%
                                 | |
| 1991 | 8 | 
                                    
                                    0.4%
                                 | |
| 1992 | 11 | 
                                    
                                    0.5%
                                 | |
| 1993 | 19 | 
                                    
                                    0.9%
                                 | |
| 1994 | 24 | 
                                    
                                    1.1%
                                 | |
| 1995 | 28 | 
                                    
                                    1.3%
                                 | |
| 1996 | 26 | 
                                    
                                    1.2%
                                 | |
| 1997 | 33 | 
                                    
                                    1.5%
                                 | |
| 1998 | 43 | 
                                    
                                    2%
                                 | |
| 1999 | 42 | 
                                    
                                    2%
                                 | |
| 2000 | 62 | 
                                    
                                    2.9%
                                 | |
| 2001 | 22 | 
                                    
                                    1%
                                 | |
| 2002 | 38 | 
                                    
                                    1.8%
                                 | |
| 2003 | 38 | 
                                    
                                    1.8%
                                 | |
| 2004 | 41 | 
                                    
                                    1.9%
                                 | |
| 2005 | 47 | 
                                    
                                    2.2%
                                 | |
| 2006 | 50 | 
                                    
                                    2.3%
                                 | |
| 2007 | 52 | 
                                    
                                    2.4%
                                 | |
| 2008 | 62 | 
                                    
                                    2.9%
                                 | |
| 2009 | 69 | 
                                    
                                    3.2%
                                 | |
| 2010 | 69 | 
                                    
                                    3.2%
                                 | |
| 2011 | 52 | 
                                    
                                    2.4%
                                 | |
| 2012 | 58 | 
                                    
                                    2.7%
                                 | |
| 2013 | 52 | 
                                    
                                    2.4%
                                 | |
| 2014 | 63 | 
                                    
                                    2.9%
                                 | |
| 2015 | 67 | 
                                    
                                    3.1%
                                 | |
| 2016 | 64 | 
                                    
                                    3%
                                 | |
| 2017 | 91 | 
                                    
                                    4.2%
                                 | |
| 2018 | 40 | 
                                    
                                    1.9%
                                 | |
| 2019 | 2 | 
                                    
                                    0.1%
                                 | |
| 9998 | DK | 39 | 
                                    
                                    1.8%
                                 | 
| 9999 | NO RESPONSE | 1 | 
                                    
                                    0%
                                 | 
| Sysmiss | 799 | 
                                    
                                    37.1%
                                 |