| Year | Count |
|---|---|
| 1974 | 6 |
| 1975 | 37 |
| 1976 | 17 |
| 1977 | 129 |
| 1978 | 129 |
| 1979 | 111 |
| 1980 | 191 |
| 1981 | 212 |
| 1982 | 322 |
| 1983 | 357 |
| 1984 | 332 |
| 1985 | 206 |
| 1986 | 136 |
| 1987 | 128 |
| 1988 | 131 |
| 1989 | 100 |
| 1990 | 99 |
| 1991 | 108 |
| 1992 | 104 |
| 1993 | 167 |
| 1994 | 85 |
| 1995 | 202 |
| 1996 | 204 |
| 1997 | 138 |
| 1998 | 146 |
| 1999 | 170 |
| 2000 | 138 |
| 2001 | 136 |
| 2002 | 101 |
| 2003 | 191 |
| 2004 | 237 |
| 2005 | 275 |
| 2006 | 248 |
| 2007 | 206 |
| 2008 | 206 |
| 2009 | 115 |
| 2010 | 134 |
| 2011 | 69 |
| 2012 | 56 |
| 2013 | 48 |
| 2014 | 38 |
| 2016 | 12 |
| 2017 | 18 |
| 2020 | 6 |
| 2022 | 16 |