| Year | Count |
|---|---|
| 1975 | 11 |
| 1977 | 5 |
| 1978 | 55 |
| 1979 | 5 |
| 1979 | 73 |
| 1980 | 57 |
| 1981 | 17 |
| 1982 | 16 |
| 1983 | 39 |
| 1984 | 7 |
| 1985 | 54 |
| 1986 | 55 |
| 1987 | 20 |
| 1988 | 31 |
| 1989 | 56 |
| 1990 | 37 |
| 1991 | 87 |
| 1992 | 160 |
| 1993 | 150 |
| 1994 | 157 |
| 1995 | 174 |
| 1996 | 141 |
| 1997 | 170 |
| 1998 | 178 |
| 1999 | 167 |
| 2000 | 237 |
| 2001 | 209 |
| 2002 | 187 |
| 2003 | 149 |
| 2004 | 181 |
| 2005 | 196 |
| 2006 | 254 |
| 2007 | 183 |
| 2008 | 190 |
| 2009 | 140 |
| 2010 | 111 |
| 2011 | 118 |
| 2012 | 100 |
| 2013 | 50 |
| 2014 | 82 |
| 2015 | 74 |
| 2016 | 71 |
| 2017 | 72 |
| 2018 | 72 |
| 2019 | 37 |
| 2020 | 21 |
| 2021 | 15 |
| 2022 | 27 |
| 2023 | 23 |