| Year | Count |
|---|---|
| 1990 | 5 |
| 1991 | 8 |
| 1992 | 6 |
| 1993 | 11 |
| 1994 | 9 |
| 1995 | 10 |
| 1996 | 13 |
| 1997 | 22 |
| 1998 | 25 |
| 1999 | 29 |
| 2000 | 28 |
| 2001 | 18 |
| 2002 | 21 |
| 2003 | 19 |
| 2004 | 20 |
| 2005 | 101 |
| 2006 | 129 |
| 2007 | 166 |
| 2008 | 160 |
| 2009 | 151 |
| 2010 | 129 |
| 2011 | 135 |
| 2012 | 131 |
| 2013 | 118 |
| 2014 | 126 |
| 2015 | 167 |
| 2016 | 471 |
| 2017 | 477 |
| 2018 | 537 |
| 2019 | 358 |
| 2020 | 380 |
| 2021 | 346 |
| 2022 | 386 |
| 2023 | 348 |
| 2024 | 334 |