| Year | Count |
|---|---|
| 1975 | 11 |
| 1976 | 15 |
| 1979 | 6 |
| 1980 | 44 |
| 1981 | 50 |
| 1982 | 16 |
| 1983 | 21 |
| 1984 | 68 |
| 1985 | 139 |
| 1986 | 103 |
| 1987 | 120 |
| 1988 | 128 |
| 1989 | 144 |
| 1990 | 121 |
| 1991 | 209 |
| 1992 | 240 |
| 1993 | 202 |
| 1994 | 170 |
| 1995 | 205 |
| 1996 | 171 |
| 1997 | 117 |
| 1998 | 180 |
| 1999 | 171 |
| 2000 | 133 |
| 2001 | 141 |
| 2002 | 65 |
| 2003 | 78 |
| 2004 | 42 |
| 2005 | 35 |
| 2006 | 43 |
| 2007 | 68 |
| 2008 | 34 |
| 2009 | 12 |
| 2010 | 12 |