| Year | Count |
|---|---|
| 1972 | 6 |
| 1973 | 5 |
| 1974 | 8 |
| 1975 | 6 |
| 1977 | 10 |
| 1981 | 5 |
| 1982 | 6 |
| 1983 | 7 |
| 1984 | 8 |
| 1986 | 6 |
| 1987 | 5 |
| 1988 | 13 |
| 1989 | 11 |
| 1990 | 11 |
| 1991 | 11 |
| 1992 | 16 |
| 1993 | 22 |
| 1994 | 18 |
| 1995 | 20 |
| 1996 | 14 |
| 1997 | 27 |
| 1998 | 31 |
| 1999 | 16 |
| 2000 | 32 |
| 2001 | 39 |
| 2002 | 34 |
| 2003 | 32 |
| 2004 | 29 |
| 2005 | 31 |
| 2006 | 39 |
| 2007 | 39 |
| 2008 | 33 |
| 2009 | 32 |
| 2010 | 42 |
| 2011 | 52 |
| 2012 | 36 |
| 2013 | 55 |
| 2014 | 70 |
| 2015 | 68 |
| 2016 | 210 |
| 2017 | 231 |
| 2018 | 195 |
| 2019 | 176 |
| 2020 | 184 |
| 2021 | 188 |
| 2022 | 226 |
| 2023 | 238 |
| 2024 | 272 |