| Year | Count |
|---|---|
| 1964 | 15 |
| 1965 | 5 |
| 1966 | 20 |
| 1967 | 24 |
| 1968 | 49 |
| 1969 | 118 |
| 1970 | 184 |
| 1971 | 546 |
| 1972 | 879 |
| 1973 | 1,269 |
| 1974 | 1,557 |
| 1975 | 1,553 |
| 1976 | 1,748 |
| 1977 | 2,097 |
| 1978 | 1,827 |
| 1979 | 2,287 |
| 1980 | 2,680 |
| 1981 | 2,623 |
| 1982 | 2,441 |
| 1983 | 2,023 |
| 1984 | 1,992 |
| 1985 | 1,647 |
| 1986 | 1,532 |
| 1987 | 1,569 |
| 1988 | 1,418 |
| 1989 | 1,295 |
| 1989 | 8 |
| 1990 | 857 |
| 1991 | 847 |
| 1992 | 622 |
| 1993 | 442 |
| 1994 | 320 |
| 1995 | 251 |
| 1996 | 155 |
| 1997 | 76 |
| 1998 | 89 |
| 1999 | 55 |
| 2000 | 32 |
| 2001 | 16 |
| 2002 | 10 |
| 2003 | 26 |