| Year | Count |
|---|---|
| 1981 | 10 |
| 1986 | 7 |
| 1987 | 10 |
| 1989 | 5 |
| 1990 | 27 |
| 1991 | 12 |
| 1992 | 32 |
| 1993 | 47 |
| 1994 | 60 |
| 1995 | 90 |
| 1996 | 98 |
| 1997 | 126 |
| 1998 | 124 |
| 1999 | 95 |
| 2000 | 104 |
| 2001 | 214 |
| 2002 | 173 |
| 2003 | 203 |
| 2004 | 340 |
| 2005 | 242 |
| 2006 | 259 |
| 2007 | 221 |
| 2008 | 222 |
| 2009 | 250 |
| 2010 | 237 |
| 2011 | 200 |
| 2012 | 340 |
| 2013 | 246 |
| 2014 | 249 |
| 2015 | 335 |
| 2016 | 307 |
| 2017 | 340 |
| 2018 | 335 |
| 2019 | 445 |
| 2020 | 440 |
| 2021 | 507 |
| 2022 | 503 |
| 2023 | 451 |
| 2024 | 455 |