| Year | Count |
|---|---|
| 1981 | 5 |
| 1984 | 5 |
| 1985 | 6 |
| 1986 | 13 |
| 1987 | 22 |
| 1988 | 19 |
| 1989 | 37 |
| 1990 | 39 |
| 1991 | 46 |
| 1992 | 53 |
| 1993 | 50 |
| 1994 | 41 |
| 1995 | 33 |
| 1996 | 86 |
| 1997 | 127 |
| 1998 | 192 |
| 1999 | 204 |
| 2000 | 149 |
| 2001 | 104 |
| 2002 | 36 |
| 2003 | 51 |
| 2004 | 26 |
| 2005 | 46 |
| 2006 | 28 |
| 2007 | 6 |
| 2008 | 32 |
| 2009 | 24 |
| 2010 | 7 |
| 2011 | 10 |
| 2014 | 5 |
| 2016 | 14 |
| 2017 | 12 |
| 2018 | 10 |
| 2020 | 11 |
| 2021 | 18 |
| 2022 | 6 |
| 2023 | 5 |