| Value | Category | Cases | |
|---|---|---|---|
| 0 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 99 | ND | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 1968 | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 1969 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1970 | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 1973 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1974 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1975 | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 1976 | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 1977 | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 1978 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1980 | 6 | 
                                                                 
                                    
                                    1.9%
                                 
                                                             | 
                                                        
                    |
| 1981 | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 1982 | 3 | 
                                                                 
                                    
                                    1%
                                 
                                                             | 
                                                        
                    |
| 1983 | 10 | 
                                                                 
                                    
                                    3.2%
                                 
                                                             | 
                                                        
                    |
| 1984 | 5 | 
                                                                 
                                    
                                    1.6%
                                 
                                                             | 
                                                        
                    |
| 1985 | 6 | 
                                                                 
                                    
                                    1.9%
                                 
                                                             | 
                                                        
                    |
| 1986 | 10 | 
                                                                 
                                    
                                    3.2%
                                 
                                                             | 
                                                        
                    |
| 1987 | 9 | 
                                                                 
                                    
                                    2.9%
                                 
                                                             | 
                                                        
                    |
| 1988 | 12 | 
                                                                 
                                    
                                    3.8%
                                 
                                                             | 
                                                        
                    |
| 1989 | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 1990 | 10 | 
                                                                 
                                    
                                    3.2%
                                 
                                                             | 
                                                        
                    |
| 1991 | 3 | 
                                                                 
                                    
                                    1%
                                 
                                                             | 
                                                        
                    |
| 1992 | 5 | 
                                                                 
                                    
                                    1.6%
                                 
                                                             | 
                                                        
                    |
| 1993 | 11 | 
                                                                 
                                    
                                    3.5%
                                 
                                                             | 
                                                        
                    |
| 1994 | 7 | 
                                                                 
                                    
                                    2.2%
                                 
                                                             | 
                                                        
                    |
| 1995 | 10 | 
                                                                 
                                    
                                    3.2%
                                 
                                                             | 
                                                        
                    |
| 1996 | 14 | 
                                                                 
                                    
                                    4.4%
                                 
                                                             | 
                                                        
                    |
| 1997 | 5 | 
                                                                 
                                    
                                    1.6%
                                 
                                                             | 
                                                        
                    |
| 1998 | 20 | 
                                                                 
                                    
                                    6.3%
                                 
                                                             | 
                                                        
                    |
| 1999 | 3 | 
                                                                 
                                    
                                    1%
                                 
                                                             | 
                                                        
                    |
| 2000 | 23 | 
                                                                 
                                    
                                    7.3%
                                 
                                                             | 
                                                        
                    |
| 2001 | 11 | 
                                                                 
                                    
                                    3.5%
                                 
                                                             | 
                                                        
                    |
| 2002 | 9 | 
                                                                 
                                    
                                    2.9%
                                 
                                                             | 
                                                        
                    |
| 2003 | 9 | 
                                                                 
                                    
                                    2.9%
                                 
                                                             | 
                                                        
                    |
| 2004 | 7 | 
                                                                 
                                    
                                    2.2%
                                 
                                                             | 
                                                        
                    |
| 2005 | 9 | 
                                                                 
                                    
                                    2.9%
                                 
                                                             | 
                                                        
                    |
| 2006 | 21 | 
                                                                 
                                    
                                    6.7%
                                 
                                                             | 
                                                        
                    |
| 2007 | 12 | 
                                                                 
                                    
                                    3.8%
                                 
                                                             | 
                                                        
                    |
| 2008 | 13 | 
                                                                 
                                    
                                    4.1%
                                 
                                                             | 
                                                        
                    |
| 2009 | 7 | 
                                                                 
                                    
                                    2.2%
                                 
                                                             | 
                                                        
                    |
| 2010 | 14 | 
                                                                 
                                    
                                    4.4%
                                 
                                                             | 
                                                        
                    |
| 2011 | 11 | 
                                                                 
                                    
                                    3.5%
                                 
                                                             | 
                                                        
                    |
| 2013 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 1185 |