| Year | Count |
|---|---|
| 1971 | 12 |
| 1972 | 6 |
| 1973 | 8 |
| 1974 | 7 |
| 1977 | 14 |
| 1978 | 23 |
| 1979 | 18 |
| 1980 | 15 |
| 1982 | 32 |
| 1983 | 10 |
| 1984 | 8 |
| 1985 | 5 |
| 1987 | 6 |
| 1988 | 5 |
| 1992 | 6 |
| 1993 | 14 |
| 1994 | 13 |
| 1995 | 13 |
| 1996 | 17 |
| 1997 | 24 |
| 1998 | 22 |
| 1999 | 11 |
| 2001 | 7 |
| 2003 | 18 |
| 2004 | 11 |
| 2005 | 23 |
| 2006 | 18 |
| 2007 | 28 |
| 2008 | 38 |
| 2009 | 57 |
| 2010 | 63 |
| 2011 | 71 |
| 2012 | 104 |
| 2013 | 104 |
| 2014 | 119 |
| 2015 | 103 |
| 2016 | 162 |
| 2017 | 195 |
| 2018 | 193 |
| 2019 | 261 |
| 2020 | 214 |
| 2021 | 277 |
| 2022 | 304 |
| 2023 | 304 |
| 2024 | 305 |