| Year | Count |
|---|---|
| 1949 | 6 |
| 1950 | 5 |
| 1951 | 9 |
| 1952 | 28 |
| 1953 | 33 |
| 1954 | 44 |
| 1955 | 42 |
| 1956 | 81 |
| 1957 | 80 |
| 1958 | 91 |
| 1959 | 99 |
| 1960 | 215 |
| 1961 | 195 |
| 1962 | 174 |
| 1963 | 275 |
| 1964 | 353 |
| 1965 | 431 |
| 1966 | 497 |
| 1967 | 684 |
| 1968 | 774 |
| 1969 | 794 |
| 1970 | 1,033 |
| 1971 | 1,069 |
| 1972 | 821 |
| 1973 | 724 |
| 1974 | 733 |
| 1975 | 694 |
| 1976 | 492 |
| 1977 | 479 |
| 1978 | 452 |
| 1979 | 410 |
| 1980 | 356 |
| 1981 | 361 |
| 1982 | 250 |
| 1983 | 174 |
| 1984 | 146 |
| 1985 | 193 |
| 1986 | 100 |
| 1987 | 26 |
| 1988 | 86 |
| 1989 | 22 |
| 1990 | 34 |
| 1991 | 11 |
| 1992 | 41 |
| 1993 | 20 |
| 1995 | 6 |
| 1998 | 7 |
| 2003 | 5 |
| 2004 | 12 |
| 2005 | 5 |