| Year | Count |
|---|---|
| 1971 | 7 |
| 1972 | 5 |
| 1973 | 8 |
| 1974 | 9 |
| 1975 | 5 |
| 1976 | 6 |
| 1977 | 5 |
| 1980 | 6 |
| 1981 | 6 |
| 1990 | 5 |
| 1994 | 7 |
| 1996 | 6 |
| 1998 | 12 |
| 1999 | 8 |
| 2000 | 9 |
| 2001 | 21 |
| 2002 | 23 |
| 2003 | 18 |
| 2004 | 15 |
| 2005 | 20 |
| 2006 | 24 |
| 2007 | 23 |
| 2008 | 28 |
| 2009 | 13 |
| 2010 | 32 |
| 2011 | 16 |
| 2012 | 21 |
| 2013 | 26 |
| 2014 | 12 |
| 2015 | 26 |
| 2016 | 38 |
| 2017 | 54 |
| 2018 | 30 |
| 2019 | 28 |
| 2020 | 18 |
| 2021 | 32 |
| 2022 | 25 |
| 2023 | 38 |
| 2024 | 32 |