| Year | Count |
|---|---|
| 1988 | 6 |
| 1989 | 11 |
| 1990 | 52 |
| 1991 | 19 |
| 1992 | 83 |
| 1993 | 34 |
| 1994 | 46 |
| 1995 | 42 |
| 1996 | 35 |
| 1997 | 46 |
| 1998 | 63 |
| 1999 | 21 |
| 2000 | 75 |
| 2001 | 100 |
| 2002 | 52 |
| 2003 | 30 |
| 2004 | 110 |
| 2005 | 130 |
| 2006 | 80 |
| 2007 | 121 |
| 2008 | 110 |
| 2009 | 120 |
| 2010 | 168 |
| 2011 | 262 |
| 2012 | 356 |
| 2013 | 111 |
| 2014 | 193 |
| 2015 | 444 |
| 2016 | 489 |
| 2017 | 523 |
| 2018 | 430 |
| 2019 | 427 |
| 2020 | 399 |
| 2021 | 423 |
| 2022 | 459 |
| 2023 | 438 |
| 2024 | 478 |