| Year | Count |
|---|---|
| 1970 | 6 |
| 1971 | 5 |
| 1973 | 7 |
| 1977 | 5 |
| 1978 | 6 |
| 1980 | 7 |
| 1982 | 9 |
| 1985 | 9 |
| 1986 | 7 |
| 1988 | 8 |
| 1989 | 15 |
| 1990 | 12 |
| 1991 | 10 |
| 1992 | 14 |
| 1993 | 19 |
| 1994 | 16 |
| 1995 | 17 |
| 1996 | 22 |
| 1997 | 26 |
| 1998 | 17 |
| 1999 | 30 |
| 2000 | 23 |
| 2001 | 32 |
| 2005 | 44 |
| 2006 | 53 |
| 2007 | 43 |
| 2008 | 47 |
| 2009 | 58 |
| 2010 | 49 |
| 2011 | 18 |
| 2012 | 100 |
| 2013 | 76 |
| 2014 | 38 |
| 2015 | 84 |
| 2016 | 90 |
| 2017 | 31 |
| 2018 | 40 |
| 2019 | 51 |
| 2021 | 73 |
| 2022 | 85 |
| 2023 | 53 |
| 2024 | 140 |