| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 12 | 
                                                                 
                                    
                                    1.8%
                                 
                                                             | 
                                                        
                    
| 1979 | 1 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1982 | 1 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1984 | 1 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1988 | 1 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1990 | 1 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1991 | 1 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1992 | 1 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1993 | 2 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1994 | 1 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1995 | 1 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1996 | 3 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    |
| 1998 | 2 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1999 | 4 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 2001 | 6 | 
                                                                 
                                    
                                    0.9%
                                 
                                                             | 
                                                        
                    |
| 2002 | 2 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 2003 | 7 | 
                                                                 
                                    
                                    1%
                                 
                                                             | 
                                                        
                    |
| 2004 | 16 | 
                                                                 
                                    
                                    2.4%
                                 
                                                             | 
                                                        
                    |
| 2005 | 10 | 
                                                                 
                                    
                                    1.5%
                                 
                                                             | 
                                                        
                    |
| 2006 | 20 | 
                                                                 
                                    
                                    2.9%
                                 
                                                             | 
                                                        
                    |
| 2007 | 46 | 
                                                                 
                                    
                                    6.8%
                                 
                                                             | 
                                                        
                    |
| 2008 | 73 | 
                                                                 
                                    
                                    10.7%
                                 
                                                             | 
                                                        
                    |
| 2009 | 14 | 
                                                                 
                                    
                                    2.1%
                                 
                                                             | 
                                                        
                    |
| 2010 | 33 | 
                                                                 
                                    
                                    4.9%
                                 
                                                             | 
                                                        
                    |
| 2011 | 24 | 
                                                                 
                                    
                                    3.5%
                                 
                                                             | 
                                                        
                    |
| 2012 | 32 | 
                                                                 
                                    
                                    4.7%
                                 
                                                             | 
                                                        
                    |
| 2013 | 56 | 
                                                                 
                                    
                                    8.2%
                                 
                                                             | 
                                                        
                    |
| 2014 | 2 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 2015 | 6 | 
                                                                 
                                    
                                    0.9%
                                 
                                                             | 
                                                        
                    |
| 2016 | 11 | 
                                                                 
                                    
                                    1.6%
                                 
                                                             | 
                                                        
                    |
| 2017 | 15 | 
                                                                 
                                    
                                    2.2%
                                 
                                                             | 
                                                        
                    |
| 2018 | 20 | 
                                                                 
                                    
                                    2.9%
                                 
                                                             | 
                                                        
                    |
| 2019 | 34 | 
                                                                 
                                    
                                    5%
                                 
                                                             | 
                                                        
                    |
| 2020 | 42 | 
                                                                 
                                    
                                    6.2%
                                 
                                                             | 
                                                        
                    |
| 2021 | 70 | 
                                                                 
                                    
                                    10.3%
                                 
                                                             | 
                                                        
                    |
| 2022 | 99 | 
                                                                 
                                    
                                    14.6%
                                 
                                                             | 
                                                        
                    |
| 2023 | 9 | 
                                                                 
                                    
                                    1.3%
                                 
                                                             | 
                                                        
                    |
| 2052 | 1 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 752 |