| Year | Count |
|---|---|
| 1958 | 10 |
| 1959 | 30 |
| 1960 | 42 |
| 1961 | 46 |
| 1962 | 122 |
| 1963 | 229 |
| 1964 | 406 |
| 1965 | 515 |
| 1966 | 588 |
| 1967 | 778 |
| 1968 | 1,139 |
| 1969 | 1,325 |
| 1970 | 1,423 |
| 1971 | 1,503 |
| 1972 | 1,317 |
| 1973 | 1,391 |
| 1974 | 1,136 |
| 1975 | 1,211 |
| 1976 | 999 |
| 1977 | 1,084 |
| 1978 | 921 |
| 1979 | 1,033 |
| 1980 | 865 |
| 1981 | 727 |
| 1982 | 706 |
| 1983 | 871 |
| 1984 | 856 |
| 1985 | 873 |
| 1986 | 789 |
| 1987 | 929 |
| 1988 | 962 |
| 1989 | 858 |
| 1990 | 613 |
| 1991 | 624 |
| 1992 | 502 |
| 1993 | 372 |
| 1994 | 294 |
| 1995 | 149 |
| 1996 | 124 |
| 1997 | 80 |
| 1998 | 71 |
| 1999 | 14 |
| 2000 | 17 |
| 2002 | 7 |
| 2003 | 5 |
| 2004 | 28 |
| 2018 | 5 |