| Value | Category | Cases | |
|---|---|---|---|
| -2 | don't know | 102 | 
                                                                 
                                    
                                    33.7%
                                 
                                                             | 
                                                        
                    
| 1959 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1960 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1967 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1969 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1970 | 4 | 
                                                                 
                                    
                                    1.3%
                                 
                                                             | 
                                                        
                    |
| 1974 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1975 | 5 | 
                                                                 
                                    
                                    1.7%
                                 
                                                             | 
                                                        
                    |
| 1978 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1979 | 2 | 
                                                                 
                                    
                                    0.7%
                                 
                                                             | 
                                                        
                    |
| 1980 | 9 | 
                                                                 
                                    
                                    3%
                                 
                                                             | 
                                                        
                    |
| 1981 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1982 | 3 | 
                                                                 
                                    
                                    1%
                                 
                                                             | 
                                                        
                    |
| 1983 | 2 | 
                                                                 
                                    
                                    0.7%
                                 
                                                             | 
                                                        
                    |
| 1984 | 4 | 
                                                                 
                                    
                                    1.3%
                                 
                                                             | 
                                                        
                    |
| 1985 | 14 | 
                                                                 
                                    
                                    4.6%
                                 
                                                             | 
                                                        
                    |
| 1986 | 8 | 
                                                                 
                                    
                                    2.6%
                                 
                                                             | 
                                                        
                    |
| 1987 | 11 | 
                                                                 
                                    
                                    3.6%
                                 
                                                             | 
                                                        
                    |
| 1988 | 12 | 
                                                                 
                                    
                                    4%
                                 
                                                             | 
                                                        
                    |
| 1989 | 12 | 
                                                                 
                                    
                                    4%
                                 
                                                             | 
                                                        
                    |
| 1990 | 14 | 
                                                                 
                                    
                                    4.6%
                                 
                                                             | 
                                                        
                    |
| 1991 | 6 | 
                                                                 
                                    
                                    2%
                                 
                                                             | 
                                                        
                    |
| 1992 | 5 | 
                                                                 
                                    
                                    1.7%
                                 
                                                             | 
                                                        
                    |
| 1993 | 4 | 
                                                                 
                                    
                                    1.3%
                                 
                                                             | 
                                                        
                    |
| 1994 | 2 | 
                                                                 
                                    
                                    0.7%
                                 
                                                             | 
                                                        
                    |
| 1995 | 4 | 
                                                                 
                                    
                                    1.3%
                                 
                                                             | 
                                                        
                    |
| 1996 | 5 | 
                                                                 
                                    
                                    1.7%
                                 
                                                             | 
                                                        
                    |
| 1997 | 7 | 
                                                                 
                                    
                                    2.3%
                                 
                                                             | 
                                                        
                    |
| 1998 | 9 | 
                                                                 
                                    
                                    3%
                                 
                                                             | 
                                                        
                    |
| 1999 | 8 | 
                                                                 
                                    
                                    2.6%
                                 
                                                             | 
                                                        
                    |
| 2000 | 9 | 
                                                                 
                                    
                                    3%
                                 
                                                             | 
                                                        
                    |
| 2001 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 2002 | 5 | 
                                                                 
                                    
                                    1.7%
                                 
                                                             | 
                                                        
                    |
| 2003 | 2 | 
                                                                 
                                    
                                    0.7%
                                 
                                                             | 
                                                        
                    |
| 2004 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 2005 | 2 | 
                                                                 
                                    
                                    0.7%
                                 
                                                             | 
                                                        
                    |
| 2006 | 2 | 
                                                                 
                                    
                                    0.7%
                                 
                                                             | 
                                                        
                    |
| 2007 | 7 | 
                                                                 
                                    
                                    2.3%
                                 
                                                             | 
                                                        
                    |
| 2008 | 6 | 
                                                                 
                                    
                                    2%
                                 
                                                             | 
                                                        
                    |
| 2009 | 9 | 
                                                                 
                                    
                                    3%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 746 |