| Year | Count |
|---|---|
| 1967 | 42 |
| 1968 | 42 |
| 1969 | 91 |
| 1970 | 126 |
| 1971 | 357 |
| 1972 | 202 |
| 1973 | 273 |
| 1974 | 311 |
| 1975 | 270 |
| 1976 | 261 |
| 1977 | 340 |
| 1978 | 362 |
| 1979 | 386 |
| 1980 | 441 |
| 1981 | 701 |
| 1982 | 544 |
| 1983 | 469 |
| 1984 | 462 |
| 1985 | 601 |
| 1986 | 558 |
| 1987 | 527 |
| 1988 | 614 |
| 1989 | 659 |
| 1990 | 540 |
| 1991 | 721 |
| 1992 | 618 |
| 1993 | 733 |
| 1994 | 693 |
| 1995 | 645 |
| 1996 | 658 |
| 1997 | 501 |
| 1998 | 347 |
| 1999 | 187 |
| 2000 | 126 |
| 2001 | 112 |
| 2002 | 74 |
| 2003 | 86 |
| 2004 | 56 |
| 2005 | 72 |
| 2006 | 18 |
| 2007 | 33 |
| 2010 | 5 |