| Value | Category | Cases | |
|---|---|---|---|
| 1992 | 1 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    |
| 1993 | 8 | 
                                                                 
                                    
                                    1.7%
                                 
                                                             | 
                                                        
                    |
| 1998 | 1 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    |
| 1999 | 1 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    |
| 2000 | 2 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    |
| 2002 | 1 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    |
| 2003 | 2 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    |
| 2004 | 9 | 
                                                                 
                                    
                                    1.9%
                                 
                                                             | 
                                                        
                    |
| 2005 | 1 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    |
| 2007 | 2 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    |
| 2009 | 4 | 
                                                                 
                                    
                                    0.8%
                                 
                                                             | 
                                                        
                    |
| 2010 | 2 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    |
| 2011 | 318 | 
                                                                 
                                    
                                    66.3%
                                 
                                                             | 
                                                        
                    |
| 2012 | 58 | 
                                                                 
                                    
                                    12.1%
                                 
                                                             | 
                                                        
                    |
| 2013 | 20 | 
                                                                 
                                    
                                    4.2%
                                 
                                                             | 
                                                        
                    |
| 2014 | 13 | 
                                                                 
                                    
                                    2.7%
                                 
                                                             | 
                                                        
                    |
| 2015 | 16 | 
                                                                 
                                    
                                    3.3%
                                 
                                                             | 
                                                        
                    |
| 2016 | 7 | 
                                                                 
                                    
                                    1.5%
                                 
                                                             | 
                                                        
                    |
| 2017 | 4 | 
                                                                 
                                    
                                    0.8%
                                 
                                                             | 
                                                        
                    |
| 2018 | 2 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    |
| Missing value | 8 | 
                                                                 
                                    
                                    1.7%
                                 
                                                             |