| Year | Count |
|---|---|
| 1959 | 10 |
| 1963 | 8 |
| 1964 | 5 |
| 1966 | 7 |
| 1967 | 5 |
| 1968 | 6 |
| 1969 | 6 |
| 1970 | 6 |
| 1970 | 6 |
| 1973 | 5 |
| 1974 | 7 |
| 1975 | 14 |
| 1976 | 38 |
| 1976 | 5 |
| 1977 | 78 |
| 1978 | 66 |
| 1979 | 54 |
| 1980 | 38 |
| 1981 | 23 |
| 1981 | 6 |
| 1982 | 13 |
| 1983 | 17 |
| 1984 | 16 |
| 1985 | 24 |
| 1986 | 25 |
| 1987 | 49 |
| 1988 | 45 |
| 1989 | 38 |
| 1990 | 35 |
| 1991 | 25 |
| 1992 | 27 |
| 1993 | 26 |
| 1994 | 21 |
| 1995 | 11 |
| 1996 | 15 |
| 1997 | 6 |
| 1998 | 6 |
| 1999 | 7 |
| 2000 | 10 |
| 2002 | 7 |
| 2003 | 10 |
| 2006 | 7 |
| 2008 | 8 |
| 2010 | 8 |
| 2011 | 5 |