| Year | Count |
|---|---|
| 1979 | 6 |
| 1980 | 7 |
| 1981 | 13 |
| 1982 | 10 |
| 1983 | 15 |
| 1984 | 17 |
| 1985 | 12 |
| 1986 | 14 |
| 1987 | 12 |
| 1988 | 12 |
| 1989 | 31 |
| 1990 | 33 |
| 1991 | 27 |
| 1992 | 35 |
| 1993 | 35 |
| 1994 | 25 |
| 1995 | 51 |
| 1996 | 52 |
| 1997 | 65 |
| 1998 | 73 |
| 1999 | 96 |
| 2000 | 100 |
| 2001 | 137 |
| 2002 | 105 |
| 2003 | 108 |
| 2004 | 193 |
| 2005 | 179 |
| 2006 | 223 |
| 2007 | 220 |
| 2008 | 228 |
| 2009 | 196 |
| 2010 | 154 |
| 2011 | 120 |
| 2012 | 212 |
| 2013 | 163 |
| 2014 | 123 |
| 2015 | 161 |
| 2016 | 156 |
| 2017 | 127 |
| 2018 | 134 |
| 2019 | 124 |
| 2020 | 85 |
| 2021 | 129 |
| 2022 | 119 |
| 2023 | 112 |
| 2024 | 140 |