| Year | Count |
|---|---|
| 1987 | 16 |
| 1988 | 5 |
| 1989 | 34 |
| 1990 | 72 |
| 1991 | 28 |
| 1992 | 77 |
| 1993 | 75 |
| 1994 | 51 |
| 1995 | 120 |
| 1996 | 79 |
| 1997 | 110 |
| 1998 | 101 |
| 1999 | 28 |
| 2000 | 94 |
| 2001 | 26 |
| 2002 | 15 |
| 2003 | 51 |
| 2004 | 57 |
| 2005 | 100 |
| 2006 | 129 |
| 2007 | 119 |
| 2008 | 172 |
| 2009 | 71 |
| 2010 | 57 |
| 2011 | 56 |
| 2012 | 43 |
| 2013 | 18 |
| 2014 | 36 |
| 2015 | 57 |
| 2016 | 7 |
| 2017 | 5 |
| 2018 | 20 |
| 2019 | 5 |
| 2021 | 22 |