| Year | Count |
|---|---|
| 1991 | 5 |
| 1992 | 10 |
| 1993 | 39 |
| 1994 | 5 |
| 1995 | 10 |
| 1996 | 6 |
| 1997 | 5 |
| 1998 | 14 |
| 1999 | 5 |
| 2000 | 33 |
| 2001 | 20 |
| 2002 | 34 |
| 2003 | 25 |
| 2004 | 141 |
| 2005 | 227 |
| 2006 | 340 |
| 2007 | 579 |
| 2008 | 887 |
| 2009 | 1,139 |
| 2010 | 1,531 |
| 2011 | 2,108 |
| 2012 | 3,761 |
| 2013 | 4,277 |
| 2014 | 5,316 |
| 2015 | 6,432 |
| 2016 | 6,130 |
| 2017 | 6,258 |
| 2018 | 5,291 |
| 2019 | 5,119 |
| 2020 | 4,980 |
| 2021 | 5,469 |
| 2022 | 5,287 |
| 2023 | 4,765 |
| 2024 | 4,489 |