| Year | Count |
|---|---|
| 1954 | 19 |
| 1955 | 42 |
| 1956 | 91 |
| 1957 | 269 |
| 1958 | 317 |
| 1959 | 415 |
| 1960 | 651 |
| 1961 | 844 |
| 1962 | 1,146 |
| 1963 | 1,063 |
| 1964 | 1,100 |
| 1965 | 1,276 |
| 1966 | 1,595 |
| 1967 | 1,554 |
| 1968 | 1,818 |
| 1969 | 2,361 |
| 1970 | 2,902 |
| 1971 | 2,780 |
| 1972 | 2,209 |
| 1973 | 1,927 |
| 1974 | 1,769 |
| 1975 | 1,546 |
| 1976 | 1,211 |
| 1977 | 868 |
| 1978 | 834 |
| 1979 | 847 |
| 1980 | 774 |
| 1981 | 644 |
| 1982 | 510 |
| 1983 | 487 |
| 1984 | 497 |
| 1985 | 505 |
| 1986 | 403 |
| 1987 | 326 |
| 1988 | 255 |
| 1989 | 230 |
| 1990 | 128 |
| 1991 | 197 |
| 1992 | 110 |
| 1993 | 104 |
| 1994 | 41 |
| 1995 | 25 |
| 1996 | 36 |
| 1997 | 22 |
| 1998 | 44 |
| 1999 | 10 |
| 2005 | 14 |
| 2006 | 12 |