| Year | Count |
|---|---|
| 1983 | 5 |
| 1984 | 15 |
| 1985 | 9 |
| 1986 | 7 |
| 1987 | 6 |
| 1988 | 8 |
| 1990 | 7 |
| 1991 | 20 |
| 1992 | 20 |
| 1993 | 31 |
| 1994 | 17 |
| 1995 | 7 |
| 1996 | 52 |
| 1997 | 38 |
| 1998 | 36 |
| 1999 | 18 |
| 2000 | 44 |
| 2001 | 50 |
| 2002 | 15 |
| 2003 | 10 |
| 2004 | 27 |
| 2005 | 45 |
| 2006 | 75 |
| 2007 | 62 |
| 2008 | 379 |
| 2009 | 519 |
| 2010 | 357 |
| 2011 | 268 |
| 2012 | 234 |
| 2013 | 229 |
| 2014 | 200 |
| 2015 | 193 |
| 2016 | 166 |
| 2017 | 148 |
| 2018 | 98 |
| 2019 | 58 |
| 2020 | 46 |
| 2021 | 16 |
| 2022 | 43 |
| 2023 | 6 |
| 2024 | 11 |