| Year | Count |
|---|---|
| 1967 | 19 |
| 1968 | 164 |
| 1969 | 164 |
| 1970 | 282 |
| 1971 | 385 |
| 1972 | 676 |
| 1973 | 884 |
| 1974 | 1,167 |
| 1975 | 2,581 |
| 1976 | 2,288 |
| 1977 | 2,268 |
| 1978 | 2,162 |
| 1979 | 1,876 |
| 1980 | 1,661 |
| 1981 | 1,483 |
| 1982 | 1,301 |
| 1983 | 1,067 |
| 1984 | 998 |
| 1985 | 898 |
| 1986 | 658 |
| 1987 | 670 |
| 1988 | 579 |
| 1989 | 439 |
| 1989 | 14 |
| 1990 | 418 |
| 1991 | 439 |
| 1992 | 288 |
| 1993 | 227 |
| 1994 | 151 |
| 1995 | 92 |
| 1996 | 78 |
| 1997 | 72 |
| 1998 | 57 |
| 1999 | 15 |
| 2000 | 9 |
| 2002 | 16 |
| 2003 | 6 |
| 2004 | 10 |
| 2007 | 10 |