| Value | Category | Cases | |
|---|---|---|---|
| 1956 | 40 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1957 | 347 | 
                                                                 
                                    
                                    2.3%
                                 
                                                             | 
                                                        
                    |
| 1958 | 502 | 
                                                                 
                                    
                                    3.4%
                                 
                                                             | 
                                                        
                    |
| 1959 | 512 | 
                                                                 
                                    
                                    3.4%
                                 
                                                             | 
                                                        
                    |
| 1960 | 539 | 
                                                                 
                                    
                                    3.6%
                                 
                                                             | 
                                                        
                    |
| 1961 | 575 | 
                                                                 
                                    
                                    3.9%
                                 
                                                             | 
                                                        
                    |
| 1962 | 533 | 
                                                                 
                                    
                                    3.6%
                                 
                                                             | 
                                                        
                    |
| 1963 | 543 | 
                                                                 
                                    
                                    3.6%
                                 
                                                             | 
                                                        
                    |
| 1964 | 512 | 
                                                                 
                                    
                                    3.4%
                                 
                                                             | 
                                                        
                    |
| 1965 | 572 | 
                                                                 
                                    
                                    3.8%
                                 
                                                             | 
                                                        
                    |
| 1966 | 525 | 
                                                                 
                                    
                                    3.5%
                                 
                                                             | 
                                                        
                    |
| 1967 | 538 | 
                                                                 
                                    
                                    3.6%
                                 
                                                             | 
                                                        
                    |
| 1968 | 574 | 
                                                                 
                                    
                                    3.9%
                                 
                                                             | 
                                                        
                    |
| 1969 | 557 | 
                                                                 
                                    
                                    3.7%
                                 
                                                             | 
                                                        
                    |
| 1970 | 495 | 
                                                                 
                                    
                                    3.3%
                                 
                                                             | 
                                                        
                    |
| 1971 | 550 | 
                                                                 
                                    
                                    3.7%
                                 
                                                             | 
                                                        
                    |
| 1972 | 568 | 
                                                                 
                                    
                                    3.8%
                                 
                                                             | 
                                                        
                    |
| 1973 | 514 | 
                                                                 
                                    
                                    3.4%
                                 
                                                             | 
                                                        
                    |
| 1974 | 540 | 
                                                                 
                                    
                                    3.6%
                                 
                                                             | 
                                                        
                    |
| 1975 | 555 | 
                                                                 
                                    
                                    3.7%
                                 
                                                             | 
                                                        
                    |
| 1976 | 488 | 
                                                                 
                                    
                                    3.3%
                                 
                                                             | 
                                                        
                    |
| 1977 | 495 | 
                                                                 
                                    
                                    3.3%
                                 
                                                             | 
                                                        
                    |
| 1978 | 523 | 
                                                                 
                                    
                                    3.5%
                                 
                                                             | 
                                                        
                    |
| 1979 | 525 | 
                                                                 
                                    
                                    3.5%
                                 
                                                             | 
                                                        
                    |
| 1980 | 506 | 
                                                                 
                                    
                                    3.4%
                                 
                                                             | 
                                                        
                    |
| 1981 | 434 | 
                                                                 
                                    
                                    2.9%
                                 
                                                             | 
                                                        
                    |
| 1982 | 415 | 
                                                                 
                                    
                                    2.8%
                                 
                                                             | 
                                                        
                    |
| 1983 | 349 | 
                                                                 
                                    
                                    2.3%
                                 
                                                             | 
                                                        
                    |
| 1984 | 284 | 
                                                                 
                                    
                                    1.9%
                                 
                                                             | 
                                                        
                    |
| 1985 | 257 | 
                                                                 
                                    
                                    1.7%
                                 
                                                             | 
                                                        
                    |
| 1986 | 184 | 
                                                                 
                                    
                                    1.2%
                                 
                                                             | 
                                                        
                    |
| 1987 | 151 | 
                                                                 
                                    
                                    1%
                                 
                                                             | 
                                                        
                    |
| 1988 | 108 | 
                                                                 
                                    
                                    0.7%
                                 
                                                             | 
                                                        
                    |
| 1989 | 62 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    |
| 1990 | 21 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1991 | 12 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    |
| 1992 | 3 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    |
| 9997 | Inconsistent | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 9998 | DK year | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 9999 | 1 |