| Year | Count |
|---|---|
| 1960 | 10 |
| 1963 | 5 |
| 1964 | 5 |
| 1965 | 26 |
| 1966 | 31 |
| 1967 | 74 |
| 1968 | 132 |
| 1969 | 162 |
| 1970 | 245 |
| 1971 | 274 |
| 1972 | 218 |
| 1973 | 255 |
| 1974 | 222 |
| 1975 | 174 |
| 1976 | 94 |
| 1977 | 74 |
| 1978 | 34 |
| 1979 | 28 |
| 1980 | 6 |
| 1981 | 16 |
| 1982 | 5 |
| 1983 | 20 |
| 1986 | 10 |
| 1987 | 18 |
| 1988 | 12 |
| 1989 | 24 |
| 1990 | 10 |
| 1991 | 26 |
| 1992 | 18 |
| 1993 | 28 |
| 1994 | 30 |
| 1995 | 26 |
| 1996 | 17 |
| 1997 | 10 |
| 2002 | 5 |
| 2004 | 5 |
| 2006 | 7 |
| 2007 | 5 |
| 2009 | 6 |