| Year | Count |
|---|---|
| 1973 | 11 |
| 1974 | 25 |
| 1975 | 11 |
| 1976 | 6 |
| 1977 | 13 |
| 1978 | 17 |
| 1979 | 5 |
| 1982 | 10 |
| 1983 | 6 |
| 1984 | 6 |
| 1986 | 10 |
| 1987 | 16 |
| 1988 | 5 |
| 1994 | 5 |
| 1997 | 5 |
| 1998 | 5 |
| 1999 | 8 |
| 2000 | 6 |
| 2001 | 6 |
| 2002 | 22 |
| 2003 | 23 |
| 2004 | 39 |
| 2005 | 44 |
| 2006 | 31 |
| 2007 | 33 |
| 2008 | 18 |
| 2009 | 15 |
| 2010 | 15 |
| 2011 | 12 |
| 2012 | 22 |
| 2013 | 5 |
| 2014 | 15 |
| 2015 | 6 |
| 2016 | 11 |
| 2017 | 10 |
| 2018 | 10 |
| 2019 | 11 |
| 2022 | 7 |