| Year | Count |
|---|---|
| 1982 | 17 |
| 1984 | 5 |
| 1985 | 15 |
| 1985 | 15 |
| 1986 | 7 |
| 1987 | 7 |
| 1988 | 8 |
| 1988 | 12 |
| 1989 | 10 |
| 1995 | 103 |
| 1995 | 291 |
| 1996 | 82 |
| 1996 | 675 |
| 1997 | 73 |
| 1997 | 588 |
| 1998 | 57 |
| 1998 | 594 |
| 1999 | 68 |
| 1999 | 414 |
| 2000 | 42 |
| 2000 | 430 |
| 2001 | 14 |
| 2001 | 499 |
| 2002 | 74 |
| 2002 | 516 |
| 2003 | 51 |
| 2003 | 490 |
| 2004 | 90 |
| 2004 | 404 |
| 2005 | 57 |
| 2005 | 500 |
| 2006 | 69 |
| 2006 | 502 |
| 2007 | 50 |
| 2007 | 473 |
| 2008 | 498 |
| 2009 | 10 |
| 2009 | 487 |
| 2010 | 14 |
| 2010 | 461 |
| 2011 | 281 |
| 2012 | 307 |
| 2013 | 235 |
| 2014 | 185 |
| 2015 | 163 |
| 2016 | 179 |
| 2017 | 109 |
| 2018 | 91 |
| 2019 | 34 |
| 2020 | 16 |
| 2021 | 24 |
| 2022 | 9 |
| 2023 | 8 |