| Year | Count |
|---|---|
| 1988 | 6 |
| 1989 | 5 |
| 1990 | 10 |
| 1991 | 5 |
| 1992 | 22 |
| 1993 | 6 |
| 1994 | 8 |
| 1995 | 9 |
| 1996 | 9 |
| 1997 | 19 |
| 1998 | 10 |
| 1999 | 15 |
| 2000 | 19 |
| 2001 | 6 |
| 2003 | 22 |
| 2004 | 18 |
| 2005 | 20 |
| 2006 | 42 |
| 2007 | 6 |
| 2008 | 26 |
| 2009 | 31 |
| 2010 | 101 |
| 2011 | 90 |
| 2012 | 74 |
| 2013 | 49 |
| 2014 | 55 |
| 2015 | 61 |
| 2016 | 50 |
| 2017 | 61 |
| 2019 | 12 |
| 2020 | 14 |
| 2021 | 32 |
| 2022 | 10 |
| 2023 | 21 |