| Value | Category | Cases | |
|---|---|---|---|
| 1992 | 3 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    |
| 1993 | 9 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    |
| 1994 | 31 | 
                                                                 
                                    
                                    1.8%
                                 
                                                             | 
                                                        
                    |
| 1995 | 25 | 
                                                                 
                                    
                                    1.5%
                                 
                                                             | 
                                                        
                    |
| 1996 | 21 | 
                                                                 
                                    
                                    1.2%
                                 
                                                             | 
                                                        
                    |
| 1997 | 23 | 
                                                                 
                                    
                                    1.3%
                                 
                                                             | 
                                                        
                    |
| 1998 | 23 | 
                                                                 
                                    
                                    1.3%
                                 
                                                             | 
                                                        
                    |
| 1999 | 40 | 
                                                                 
                                    
                                    2.3%
                                 
                                                             | 
                                                        
                    |
| 2000 | 69 | 
                                                                 
                                    
                                    4%
                                 
                                                             | 
                                                        
                    |
| 2001 | 54 | 
                                                                 
                                    
                                    3.2%
                                 
                                                             | 
                                                        
                    |
| 2002 | 72 | 
                                                                 
                                    
                                    4.2%
                                 
                                                             | 
                                                        
                    |
| 2003 | 70 | 
                                                                 
                                    
                                    4.1%
                                 
                                                             | 
                                                        
                    |
| 2004 | 110 | 
                                                                 
                                    
                                    6.4%
                                 
                                                             | 
                                                        
                    |
| 2005 | 133 | 
                                                                 
                                    
                                    7.8%
                                 
                                                             | 
                                                        
                    |
| 2006 | 166 | 
                                                                 
                                    
                                    9.7%
                                 
                                                             | 
                                                        
                    |
| 2007 | 188 | 
                                                                 
                                    
                                    11%
                                 
                                                             | 
                                                        
                    |
| 2008 | 207 | 
                                                                 
                                    
                                    12.1%
                                 
                                                             | 
                                                        
                    |
| 2009 | 229 | 
                                                                 
                                    
                                    13.4%
                                 
                                                             | 
                                                        
                    |
| 2010 | 141 | 
                                                                 
                                    
                                    8.2%
                                 
                                                             | 
                                                        
                    |
| 2011 | 75 | 
                                                                 
                                    
                                    4.4%
                                 
                                                             | 
                                                        
                    |
| 2012 | 21 | 
                                                                 
                                    
                                    1.2%
                                 
                                                             |