| Year | Count |
|---|---|
| 1958 | 6 |
| 1959 | 8 |
| 1960 | 13 |
| 1961 | 12 |
| 1962 | 5 |
| 1963 | 8 |
| 1965 | 6 |
| 1967 | 7 |
| 1968 | 13 |
| 1969 | 30 |
| 1970 | 40 |
| 1971 | 47 |
| 1972 | 49 |
| 1973 | 24 |
| 1974 | 20 |
| 1975 | 36 |
| 1976 | 43 |
| 1977 | 20 |
| 1978 | 23 |
| 1979 | 42 |
| 1980 | 37 |
| 1981 | 34 |
| 1982 | 28 |
| 1983 | 21 |
| 1984 | 22 |
| 1985 | 54 |
| 1986 | 32 |
| 1987 | 22 |
| 1988 | 8 |
| 1992 | 5 |
| 1995 | 11 |
| 1996 | 13 |
| 1997 | 10 |
| 1998 | 39 |
| 2004 | 12 |
| 2007 | 12 |
| 2008 | 9 |
| 2011 | 5 |
| 2014 | 5 |