| Year | Count |
|---|---|
| 1955 | 7 |
| 1956 | 22 |
| 1959 | 12 |
| 1960 | 5 |
| 1961 | 18 |
| 1962 | 10 |
| 1963 | 15 |
| 1967 | 6 |
| 1968 | 6 |
| 1969 | 5 |
| 1970 | 6 |
| 1971 | 16 |
| 1972 | 15 |
| 1978 | 7 |
| 1979 | 15 |
| 1980 | 21 |
| 1981 | 5 |
| 1982 | 13 |
| 1984 | 9 |
| 1985 | 39 |
| 1987 | 12 |
| 1988 | 10 |
| 1989 | 10 |
| 1990 | 12 |
| 1991 | 10 |
| 1992 | 6 |
| 1996 | 10 |
| 1997 | 14 |
| 1998 | 33 |
| 2003 | 14 |
| 2004 | 5 |
| 2006 | 7 |