| Year | Count |
|---|---|
| 1968 | 6 |
| 1973 | 10 |
| 1981 | 6 |
| 1983 | 7 |
| 1986 | 10 |
| 1988 | 5 |
| 1989 | 12 |
| 1991 | 10 |
| 1992 | 5 |
| 1993 | 5 |
| 1994 | 19 |
| 1995 | 30 |
| 1996 | 36 |
| 1997 | 26 |
| 1998 | 91 |
| 1999 | 52 |
| 2000 | 22 |
| 2001 | 53 |
| 2002 | 50 |
| 2003 | 47 |
| 2004 | 105 |
| 2005 | 154 |
| 2006 | 147 |
| 2007 | 262 |
| 2008 | 300 |
| 2009 | 308 |
| 2010 | 441 |
| 2011 | 719 |
| 2012 | 1,148 |
| 2013 | 1,273 |
| 2014 | 1,449 |
| 2015 | 2,219 |
| 2016 | 2,494 |
| 2017 | 3,111 |
| 2018 | 3,132 |
| 2019 | 3,127 |
| 2020 | 2,974 |
| 2021 | 3,325 |
| 2022 | 3,538 |
| 2023 | 3,219 |
| 2024 | 3,096 |