| Value | Category | Cases | |
|---|---|---|---|
| 1968 | 1 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    |
| 1969 | 1 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    |
| 1970 | 7 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1971 | 10 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1972 | 20 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1973 | 34 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    |
| 1974 | 56 | 
                                                                 
                                    
                                    0.8%
                                 
                                                             | 
                                                        
                    |
| 1975 | 71 | 
                                                                 
                                    
                                    1%
                                 
                                                             | 
                                                        
                    |
| 1976 | 108 | 
                                                                 
                                    
                                    1.6%
                                 
                                                             | 
                                                        
                    |
| 1977 | 84 | 
                                                                 
                                    
                                    1.2%
                                 
                                                             | 
                                                        
                    |
| 1978 | 94 | 
                                                                 
                                    
                                    1.4%
                                 
                                                             | 
                                                        
                    |
| 1979 | 136 | 
                                                                 
                                    
                                    2%
                                 
                                                             | 
                                                        
                    |
| 1980 | 129 | 
                                                                 
                                    
                                    1.9%
                                 
                                                             | 
                                                        
                    |
| 1981 | 199 | 
                                                                 
                                    
                                    2.9%
                                 
                                                             | 
                                                        
                    |
| 1982 | 233 | 
                                                                 
                                    
                                    3.4%
                                 
                                                             | 
                                                        
                    |
| 1983 | 299 | 
                                                                 
                                    
                                    4.4%
                                 
                                                             | 
                                                        
                    |
| 1984 | 324 | 
                                                                 
                                    
                                    4.7%
                                 
                                                             | 
                                                        
                    |
| 1985 | 361 | 
                                                                 
                                    
                                    5.3%
                                 
                                                             | 
                                                        
                    |
| 1986 | 390 | 
                                                                 
                                    
                                    5.7%
                                 
                                                             | 
                                                        
                    |
| 1987 | 377 | 
                                                                 
                                    
                                    5.5%
                                 
                                                             | 
                                                        
                    |
| 1988 | 299 | 
                                                                 
                                    
                                    4.4%
                                 
                                                             | 
                                                        
                    |
| 1989 | 282 | 
                                                                 
                                    
                                    4.1%
                                 
                                                             | 
                                                        
                    |
| 1990 | 334 | 
                                                                 
                                    
                                    4.9%
                                 
                                                             | 
                                                        
                    |
| 1991 | 283 | 
                                                                 
                                    
                                    4.1%
                                 
                                                             | 
                                                        
                    |
| 1992 | 338 | 
                                                                 
                                    
                                    4.9%
                                 
                                                             | 
                                                        
                    |
| 1993 | 362 | 
                                                                 
                                    
                                    5.3%
                                 
                                                             | 
                                                        
                    |
| 1994 | 430 | 
                                                                 
                                    
                                    6.3%
                                 
                                                             | 
                                                        
                    |
| 1995 | 268 | 
                                                                 
                                    
                                    3.9%
                                 
                                                             | 
                                                        
                    |
| 1996 | 323 | 
                                                                 
                                    
                                    4.7%
                                 
                                                             | 
                                                        
                    |
| 1997 | 310 | 
                                                                 
                                    
                                    4.5%
                                 
                                                             | 
                                                        
                    |
| 1998 | 281 | 
                                                                 
                                    
                                    4.1%
                                 
                                                             | 
                                                        
                    |
| 1999 | 299 | 
                                                                 
                                    
                                    4.4%
                                 
                                                             | 
                                                        
                    |
| 2000 | 118 | 
                                                                 
                                    
                                    1.7%
                                 
                                                             | 
                                                        
                    |
| 9997 | inconsistent | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 9998 | dk | 1 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 8489 |