| Year | Count |
|---|---|
| 1980 | 5 |
| 1984 | 5 |
| 1986 | 10 |
| 1987 | 5 |
| 1988 | 8 |
| 1989 | 19 |
| 1991 | 6 |
| 1992 | 5 |
| 1993 | 10 |
| 1994 | 18 |
| 1995 | 9 |
| 1996 | 16 |
| 1997 | 37 |
| 1998 | 31 |
| 1999 | 19 |
| 2000 | 15 |
| 2001 | 22 |
| 2003 | 12 |
| 2005 | 22 |
| 2006 | 42 |
| 2007 | 25 |
| 2008 | 18 |
| 2009 | 25 |
| 2010 | 10 |
| 2014 | 5 |
| 2015 | 13 |
| 2016 | 19 |
| 2017 | 8 |
| 2019 | 10 |
| 2020 | 6 |
| 2022 | 5 |
| 2023 | 11 |