| Year | Count |
|---|---|
| 1971 | 5 |
| 1975 | 6 |
| 1976 | 6 |
| 1977 | 17 |
| 1981 | 7 |
| 1982 | 36 |
| 1983 | 22 |
| 1984 | 47 |
| 1985 | 55 |
| 1986 | 62 |
| 1987 | 88 |
| 1988 | 69 |
| 1989 | 122 |
| 1990 | 121 |
| 1991 | 96 |
| 1992 | 88 |
| 1993 | 73 |
| 1994 | 69 |
| 1995 | 207 |
| 1996 | 655 |
| 1997 | 394 |
| 1998 | 279 |
| 1999 | 337 |
| 2000 | 464 |
| 2001 | 287 |
| 2002 | 218 |
| 2003 | 160 |
| 2004 | 282 |
| 2005 | 164 |
| 2006 | 212 |
| 2007 | 172 |
| 2008 | 220 |
| 2009 | 184 |
| 2010 | 154 |
| 2011 | 190 |
| 2012 | 184 |
| 2013 | 178 |
| 2014 | 186 |
| 2015 | 196 |
| 2016 | 263 |
| 2017 | 232 |
| 2018 | 221 |
| 2019 | 205 |
| 2020 | 154 |
| 2021 | 280 |
| 2022 | 217 |
| 2023 | 187 |
| 2024 | 189 |