| Year | Count |
|---|---|
| 1975 | 12 |
| 1976 | 15 |
| 1977 | 16 |
| 1978 | 15 |
| 1979 | 20 |
| 1980 | 18 |
| 1981 | 26 |
| 1982 | 19 |
| 1983 | 13 |
| 1985 | 13 |
| 1986 | 32 |
| 1988 | 15 |
| 1989 | 21 |
| 1990 | 23 |
| 1991 | 54 |
| 1992 | 46 |
| 1993 | 55 |
| 1994 | 68 |
| 1995 | 60 |
| 1996 | 108 |
| 1997 | 100 |
| 1998 | 130 |
| 1999 | 184 |
| 2000 | 136 |
| 2001 | 232 |
| 2002 | 189 |
| 2003 | 140 |
| 2004 | 181 |
| 2005 | 180 |
| 2006 | 212 |
| 2007 | 198 |
| 2008 | 227 |
| 2009 | 239 |
| 2010 | 211 |
| 2011 | 233 |
| 2012 | 307 |
| 2013 | 394 |
| 2014 | 430 |
| 2015 | 441 |
| 2016 | 543 |
| 2017 | 348 |
| 2018 | 406 |
| 2019 | 370 |
| 2020 | 249 |
| 2021 | 231 |
| 2022 | 289 |
| 2023 | 291 |
| 2024 | 302 |