| Year | Count |
|---|---|
| 1959 | 5 |
| 1970 | 5 |
| 1974 | 5 |
| 1975 | 8 |
| 1978 | 6 |
| 1981 | 5 |
| 1985 | 6 |
| 1986 | 10 |
| 1987 | 24 |
| 1988 | 81 |
| 1989 | 72 |
| 1990 | 42 |
| 1991 | 122 |
| 1992 | 170 |
| 1993 | 224 |
| 1994 | 200 |
| 1995 | 213 |
| 1996 | 251 |
| 1997 | 321 |
| 1998 | 298 |
| 1999 | 225 |
| 2000 | 265 |
| 2001 | 332 |
| 2002 | 260 |
| 2003 | 339 |
| 2004 | 511 |
| 2005 | 484 |
| 2006 | 532 |
| 2007 | 625 |
| 2008 | 653 |
| 2009 | 627 |
| 2010 | 557 |
| 2011 | 596 |
| 2012 | 531 |
| 2013 | 496 |
| 2014 | 463 |
| 2015 | 435 |
| 2016 | 327 |
| 2017 | 258 |
| 2018 | 256 |
| 2019 | 235 |
| 2020 | 210 |
| 2021 | 142 |
| 2022 | 117 |
| 2023 | 145 |
| 2024 | 108 |