| Year | Count |
|---|---|
| 1969 | 5 |
| 1970 | 5 |
| 1975 | 6 |
| 1976 | 10 |
| 1978 | 18 |
| 1979 | 10 |
| 1986 | 9 |
| 1987 | 5 |
| 1988 | 6 |
| 1989 | 5 |
| 1992 | 6 |
| 1998 | 6 |
| 1999 | 7 |
| 2000 | 15 |
| 2001 | 7 |
| 2002 | 13 |
| 2003 | 11 |
| 2004 | 19 |
| 2005 | 24 |
| 2006 | 37 |
| 2007 | 45 |
| 2008 | 45 |
| 2009 | 50 |
| 2010 | 50 |
| 2011 | 53 |
| 2012 | 79 |
| 2013 | 74 |
| 2014 | 83 |
| 2015 | 78 |
| 2016 | 231 |
| 2017 | 198 |
| 2018 | 58 |
| 2019 | 120 |
| 2020 | 76 |
| 2021 | 90 |
| 2022 | 86 |
| 2023 | 84 |
| 2024 | 66 |