| Year | Count |
|---|---|
| 1975 | 8 |
| 1977 | 14 |
| 1978 | 7 |
| 1979 | 12 |
| 1980 | 13 |
| 1981 | 16 |
| 1982 | 16 |
| 1983 | 25 |
| 1984 | 6 |
| 1985 | 33 |
| 1986 | 50 |
| 1987 | 27 |
| 1988 | 37 |
| 1989 | 48 |
| 1990 | 89 |
| 1991 | 112 |
| 1992 | 130 |
| 1993 | 120 |
| 1994 | 131 |
| 1995 | 130 |
| 1996 | 169 |
| 1997 | 136 |
| 1998 | 163 |
| 1999 | 198 |
| 2000 | 203 |
| 2001 | 206 |
| 2002 | 202 |
| 2003 | 271 |
| 2004 | 235 |
| 2005 | 243 |
| 2006 | 279 |
| 2007 | 197 |
| 2008 | 269 |
| 2009 | 205 |
| 2010 | 190 |
| 2011 | 126 |
| 2012 | 107 |
| 2013 | 79 |
| 2014 | 83 |
| 2015 | 72 |
| 2016 | 72 |
| 2017 | 59 |
| 2018 | 52 |
| 2019 | 31 |
| 2020 | 33 |
| 2021 | 22 |
| 2022 | 22 |
| 2023 | 10 |
| 2024 | 5 |