| Year | Count |
|---|---|
| 1977 | 10 |
| 1984 | 10 |
| 1988 | 5 |
| 1990 | 43 |
| 1991 | 59 |
| 1992 | 47 |
| 1993 | 41 |
| 1994 | 32 |
| 1995 | 34 |
| 1996 | 58 |
| 1997 | 100 |
| 1998 | 182 |
| 1999 | 234 |
| 2000 | 333 |
| 2001 | 450 |
| 2002 | 388 |
| 2003 | 415 |
| 2004 | 587 |
| 2005 | 621 |
| 2006 | 555 |
| 2007 | 534 |
| 2008 | 603 |
| 2009 | 579 |
| 2010 | 572 |
| 2011 | 663 |
| 2012 | 739 |
| 2013 | 602 |
| 2014 | 614 |
| 2015 | 681 |
| 2016 | 710 |
| 2017 | 689 |
| 2018 | 573 |
| 2019 | 575 |
| 2020 | 446 |
| 2021 | 532 |
| 2022 | 425 |
| 2023 | 372 |
| 2024 | 301 |