| Year | Count |
|---|---|
| 1951 | 30 |
| 1952 | 5 |
| 1953 | 27 |
| 1954 | 31 |
| 1955 | 34 |
| 1956 | 53 |
| 1957 | 42 |
| 1958 | 82 |
| 1959 | 109 |
| 1960 | 111 |
| 1961 | 178 |
| 1962 | 206 |
| 1963 | 127 |
| 1964 | 184 |
| 1965 | 200 |
| 1966 | 126 |
| 1967 | 160 |
| 1968 | 175 |
| 1969 | 161 |
| 1970 | 185 |
| 1971 | 140 |
| 1972 | 107 |
| 1973 | 84 |
| 1974 | 54 |
| 1975 | 75 |
| 1976 | 70 |
| 1977 | 49 |
| 1978 | 61 |
| 1979 | 80 |
| 1980 | 66 |
| 1981 | 50 |
| 1982 | 49 |
| 1983 | 64 |
| 1984 | 69 |
| 1985 | 58 |
| 1986 | 82 |
| 1987 | 71 |
| 1988 | 91 |
| 1989 | 52 |
| 1990 | 72 |
| 1991 | 40 |
| 1992 | 75 |
| 1993 | 14 |
| 1994 | 15 |
| 1995 | 19 |
| 1996 | 12 |
| 1997 | 15 |
| 1998 | 10 |
| 2003 | 10 |
| 2005 | 10 |