| Year | Count |
|---|---|
| 1975 | 15 |
| 1976 | 100 |
| 1977 | 529 |
| 1978 | 351 |
| 1979 | 335 |
| 1980 | 233 |
| 1981 | 205 |
| 1982 | 127 |
| 1983 | 99 |
| 1984 | 94 |
| 1985 | 116 |
| 1986 | 54 |
| 1987 | 111 |
| 1988 | 49 |
| 1989 | 55 |
| 1990 | 80 |
| 1991 | 48 |
| 1992 | 50 |
| 1993 | 125 |
| 1994 | 176 |
| 1995 | 174 |
| 1996 | 120 |
| 1997 | 159 |
| 1998 | 153 |
| 1999 | 100 |
| 2000 | 114 |
| 2001 | 133 |
| 2002 | 51 |
| 2003 | 54 |
| 2004 | 96 |
| 2005 | 113 |
| 2006 | 62 |
| 2007 | 52 |
| 2008 | 28 |
| 2009 | 15 |
| 2010 | 29 |
| 2011 | 15 |
| 2012 | 5 |
| 2018 | 7 |
| 2019 | 18 |
| 2021 | 5 |