| Year | Count |
|---|---|
| 1989 | 5 |
| 1990 | 24 |
| 1991 | 28 |
| 1992 | 5 |
| 1993 | 28 |
| 1994 | 15 |
| 1995 | 23 |
| 1996 | 25 |
| 1997 | 69 |
| 1998 | 129 |
| 1999 | 65 |
| 2000 | 96 |
| 2001 | 30 |
| 2002 | 63 |
| 2003 | 94 |
| 2004 | 160 |
| 2005 | 177 |
| 2006 | 142 |
| 2007 | 146 |
| 2008 | 181 |
| 2009 | 112 |
| 2010 | 141 |
| 2011 | 188 |
| 2012 | 147 |
| 2013 | 64 |
| 2014 | 36 |
| 2015 | 35 |
| 2016 | 6 |
| 2017 | 6 |
| 2020 | 8 |
| 2021 | 5 |