| Year | Count |
|---|---|
| 1990 | 22 |
| 1991 | 94 |
| 1992 | 252 |
| 1993 | 208 |
| 1994 | 185 |
| 1995 | 159 |
| 1996 | 106 |
| 1997 | 158 |
| 1998 | 209 |
| 1999 | 172 |
| 2000 | 177 |
| 2001 | 158 |
| 2002 | 85 |
| 2003 | 137 |
| 2004 | 174 |
| 2005 | 148 |
| 2006 | 138 |
| 2007 | 59 |
| 2008 | 64 |
| 2009 | 58 |
| 2010 | 51 |
| 2011 | 17 |
| 2012 | 10 |
| 2013 | 20 |
| 2014 | 14 |
| 2015 | 12 |
| 2016 | 38 |
| 2017 | 5 |
| 2018 | 5 |