| Year | Count |
|---|---|
| 1960 | 7 |
| 1961 | 24 |
| 1962 | 11 |
| 1963 | 12 |
| 1967 | 5 |
| 1968 | 6 |
| 1969 | 11 |
| 1970 | 15 |
| 1972 | 6 |
| 1976 | 42 |
| 1977 | 5 |
| 1978 | 30 |
| 1979 | 5 |
| 1981 | 10 |
| 1982 | 21 |
| 1983 | 6 |
| 1984 | 38 |
| 1985 | 41 |
| 1986 | 65 |
| 1987 | 44 |
| 1988 | 99 |
| 1989 | 112 |
| 1990 | 123 |
| 1991 | 116 |
| 1992 | 71 |
| 1993 | 65 |
| 1994 | 45 |
| 1996 | 5 |
| 1997 | 6 |
| 1998 | 12 |
| 1999 | 5 |
| 2003 | 10 |