| Year | Count |
|---|---|
| 1968 | 5 |
| 1985 | 5 |
| 1988 | 5 |
| 1989 | 7 |
| 1990 | 8 |
| 1991 | 6 |
| 1992 | 8 |
| 1995 | 18 |
| 1996 | 12 |
| 1997 | 17 |
| 1998 | 20 |
| 1999 | 35 |
| 2000 | 30 |
| 2001 | 44 |
| 2002 | 49 |
| 2003 | 67 |
| 2004 | 70 |
| 2005 | 76 |
| 2006 | 78 |
| 2007 | 84 |
| 2008 | 70 |
| 2009 | 88 |
| 2010 | 98 |
| 2011 | 145 |
| 2012 | 184 |
| 2013 | 227 |
| 2014 | 220 |
| 2015 | 231 |
| 2016 | 456 |
| 2017 | 380 |
| 2018 | 408 |
| 2019 | 442 |
| 2020 | 177 |
| 2021 | 212 |
| 2022 | 181 |
| 2023 | 155 |
| 2024 | 174 |