| Year | Count |
|---|---|
| 1978 | 12 |
| 1979 | 10 |
| 1981 | 6 |
| 1983 | 6 |
| 1985 | 20 |
| 1986 | 29 |
| 1988 | 10 |
| 1989 | 6 |
| 1990 | 13 |
| 1991 | 5 |
| 1992 | 77 |
| 1993 | 91 |
| 1994 | 118 |
| 1995 | 57 |
| 1996 | 165 |
| 1997 | 215 |
| 1998 | 253 |
| 1999 | 244 |
| 2000 | 290 |
| 2001 | 297 |
| 2002 | 229 |
| 2003 | 258 |
| 2004 | 383 |
| 2005 | 420 |
| 2006 | 419 |
| 2007 | 374 |
| 2008 | 402 |
| 2009 | 301 |
| 2010 | 204 |
| 2011 | 313 |
| 2012 | 226 |
| 2013 | 193 |
| 2014 | 99 |
| 2015 | 156 |
| 2016 | 118 |
| 2017 | 103 |
| 2018 | 52 |
| 2019 | 33 |
| 2020 | 44 |
| 2021 | 30 |
| 2022 | 58 |
| 2023 | 38 |
| 2024 | 29 |