| Year | Count |
|---|---|
| 1970 | 5 |
| 1973 | 6 |
| 1977 | 12 |
| 1978 | 5 |
| 1979 | 30 |
| 1980 | 48 |
| 1981 | 26 |
| 1982 | 16 |
| 1983 | 8 |
| 1984 | 6 |
| 1985 | 15 |
| 1986 | 36 |
| 1987 | 14 |
| 1988 | 57 |
| 1989 | 25 |
| 1990 | 59 |
| 1991 | 80 |
| 1992 | 72 |
| 1993 | 66 |
| 1994 | 52 |
| 1995 | 49 |
| 1996 | 83 |
| 1997 | 88 |
| 1998 | 142 |
| 1999 | 80 |
| 2000 | 115 |
| 2001 | 119 |
| 2002 | 146 |
| 2003 | 225 |
| 2004 | 241 |
| 2005 | 252 |
| 2006 | 219 |
| 2007 | 222 |
| 2008 | 258 |
| 2009 | 180 |
| 2010 | 215 |
| 2011 | 182 |
| 2012 | 192 |
| 2013 | 183 |
| 2014 | 170 |
| 2015 | 175 |
| 2016 | 265 |
| 2017 | 349 |
| 2018 | 236 |
| 2019 | 227 |
| 2020 | 267 |
| 2021 | 324 |
| 2022 | 400 |
| 2023 | 393 |
| 2024 | 419 |