| Year | Count |
|---|---|
| 1986 | 10 |
| 1989 | 5 |
| 1990 | 65 |
| 1991 | 44 |
| 1992 | 69 |
| 1993 | 68 |
| 1994 | 148 |
| 1995 | 269 |
| 1996 | 262 |
| 1997 | 363 |
| 1998 | 370 |
| 1999 | 474 |
| 2000 | 491 |
| 2001 | 491 |
| 2002 | 339 |
| 2003 | 503 |
| 2004 | 488 |
| 2005 | 454 |
| 2006 | 406 |
| 2007 | 378 |
| 2008 | 368 |
| 2009 | 205 |
| 2010 | 253 |
| 2011 | 261 |
| 2012 | 129 |
| 2013 | 117 |
| 2014 | 67 |
| 2015 | 31 |
| 2016 | 59 |
| 2017 | 29 |
| 2018 | 5 |
| 2019 | 12 |
| 2021 | 7 |
| 2022 | 6 |