| Year | Count |
|---|---|
| 1957 | 12 |
| 1958 | 12 |
| 1959 | 22 |
| 1960 | 12 |
| 1961 | 8 |
| 1962 | 11 |
| 1963 | 11 |
| 1964 | 8 |
| 1965 | 7 |
| 1966 | 14 |
| 1967 | 8 |
| 1968 | 5 |
| 1969 | 9 |
| 1970 | 15 |
| 1971 | 6 |
| 1972 | 7 |
| 1975 | 7 |
| 1976 | 14 |
| 1978 | 12 |
| 1979 | 10 |
| 1982 | 5 |
| 1984 | 6 |
| 1986 | 7 |
| 1994 | 9 |
| 1995 | 10 |
| 1996 | 8 |
| 1997 | 7 |
| 1998 | 11 |
| 1999 | 14 |
| 2000 | 11 |
| 2002 | 8 |
| 2005 | 7 |
| 2006 | 5 |
| 2007 | 6 |
| 2012 | 5 |
| 2013 | 8 |