| Year | Count |
|---|---|
| 1990 | 5 |
| 1991 | 9 |
| 1992 | 13 |
| 1993 | 18 |
| 1994 | 21 |
| 1995 | 17 |
| 1996 | 43 |
| 1997 | 28 |
| 1998 | 76 |
| 1999 | 86 |
| 2000 | 110 |
| 2001 | 164 |
| 2002 | 198 |
| 2003 | 251 |
| 2004 | 298 |
| 2005 | 421 |
| 2006 | 485 |
| 2007 | 534 |
| 2008 | 663 |
| 2009 | 663 |
| 2010 | 654 |
| 2011 | 516 |
| 2012 | 483 |
| 2013 | 299 |
| 2014 | 276 |
| 2015 | 244 |
| 2016 | 294 |
| 2017 | 217 |
| 2018 | 136 |
| 2019 | 80 |
| 2020 | 93 |
| 2021 | 48 |
| 2022 | 32 |
| 2023 | 12 |
| 2024 | 22 |