| Year | Count |
|---|---|
| 1981 | 5 |
| 1982 | 5 |
| 1984 | 7 |
| 1985 | 37 |
| 1986 | 79 |
| 1987 | 64 |
| 1988 | 69 |
| 1989 | 60 |
| 1990 | 61 |
| 1991 | 94 |
| 1992 | 80 |
| 1993 | 123 |
| 1994 | 196 |
| 1995 | 216 |
| 1996 | 179 |
| 1997 | 210 |
| 1998 | 203 |
| 1999 | 219 |
| 2000 | 219 |
| 2001 | 212 |
| 2002 | 213 |
| 2003 | 197 |
| 2004 | 155 |
| 2005 | 129 |
| 2006 | 108 |
| 2007 | 92 |
| 2008 | 98 |
| 2009 | 72 |
| 2010 | 82 |
| 2011 | 46 |
| 2012 | 59 |
| 2013 | 38 |
| 2014 | 42 |
| 2015 | 34 |
| 2016 | 114 |
| 2017 | 90 |
| 2018 | 34 |
| 2019 | 66 |
| 2020 | 58 |
| 2021 | 78 |
| 2022 | 40 |
| 2023 | 42 |
| 2024 | 40 |