| Year | Count |
|---|---|
| 1979 | 6 |
| 1980 | 33 |
| 1981 | 21 |
| 1982 | 11 |
| 1983 | 5 |
| 1985 | 14 |
| 1991 | 10 |
| 1992 | 5 |
| 1994 | 10 |
| 1995 | 24 |
| 1996 | 7 |
| 1997 | 26 |
| 1998 | 34 |
| 1999 | 10 |
| 2000 | 32 |
| 2001 | 26 |
| 2002 | 25 |
| 2003 | 13 |
| 2004 | 66 |
| 2005 | 64 |
| 2006 | 89 |
| 2007 | 216 |
| 2008 | 163 |
| 2009 | 138 |
| 2010 | 141 |
| 2011 | 175 |
| 2012 | 134 |
| 2013 | 159 |
| 2014 | 84 |
| 2015 | 192 |
| 2016 | 163 |
| 2017 | 320 |
| 2018 | 392 |
| 2019 | 359 |
| 2020 | 430 |
| 2021 | 484 |
| 2022 | 566 |
| 2023 | 509 |
| 2024 | 496 |