| Year | Count |
|---|---|
| 1951 | 6 |
| 1952 | 6 |
| 1953 | 7 |
| 1954 | 7 |
| 1955 | 8 |
| 1956 | 7 |
| 1957 | 40 |
| 1958 | 24 |
| 1959 | 16 |
| 1960 | 18 |
| 1961 | 50 |
| 1963 | 29 |
| 1964 | 24 |
| 1965 | 24 |
| 1966 | 19 |
| 1967 | 31 |
| 1968 | 17 |
| 1969 | 19 |
| 1970 | 27 |
| 1971 | 22 |
| 1972 | 19 |
| 1973 | 11 |
| 1974 | 11 |
| 1975 | 8 |
| 1976 | 13 |
| 1977 | 32 |
| 1978 | 12 |
| 1979 | 18 |
| 1981 | 6 |
| 1982 | 11 |
| 1983 | 6 |
| 1984 | 9 |
| 1986 | 8 |
| 1987 | 6 |
| 1989 | 5 |
| 1993 | 6 |
| 1994 | 7 |
| 1996 | 7 |
| 1997 | 6 |
| 1999 | 5 |
| 2000 | 7 |
| 2001 | 7 |
| 2002 | 8 |
| 2003 | 5 |
| 2004 | 5 |
| 2005 | 7 |
| 2006 | 5 |
| 2007 | 6 |
| 2008 | 5 |
| 2009 | 5 |
| 2013 | 7 |
| 2014 | 12 |