| Year | Count |
|---|---|
| 1968 | 12 |
| 1970 | 5 |
| 1971 | 5 |
| 1974 | 5 |
| 1975 | 6 |
| 1977 | 5 |
| 1978 | 5 |
| 1980 | 5 |
| 1981 | 12 |
| 1983 | 5 |
| 1984 | 7 |
| 1985 | 7 |
| 1990 | 12 |
| 1991 | 9 |
| 1992 | 20 |
| 1993 | 23 |
| 1994 | 35 |
| 1995 | 24 |
| 1996 | 15 |
| 1997 | 36 |
| 1998 | 17 |
| 1999 | 38 |
| 2000 | 57 |
| 2001 | 80 |
| 2002 | 43 |
| 2003 | 108 |
| 2004 | 15 |
| 2005 | 64 |
| 2006 | 96 |
| 2007 | 207 |
| 2008 | 182 |
| 2009 | 168 |
| 2010 | 134 |
| 2011 | 125 |
| 2012 | 129 |
| 2013 | 129 |
| 2014 | 142 |
| 2015 | 143 |
| 2016 | 208 |
| 2017 | 200 |
| 2018 | 165 |
| 2019 | 131 |
| 2020 | 176 |
| 2021 | 177 |
| 2022 | 169 |
| 2023 | 138 |
| 2024 | 158 |