| Year | Count |
|---|---|
| 1973 | 10 |
| 1977 | 18 |
| 1979 | 6 |
| 1980 | 7 |
| 1981 | 8 |
| 1983 | 21 |
| 1984 | 35 |
| 1985 | 42 |
| 1986 | 67 |
| 1987 | 106 |
| 1988 | 45 |
| 1989 | 52 |
| 1990 | 61 |
| 1991 | 124 |
| 1992 | 140 |
| 1993 | 68 |
| 1994 | 66 |
| 1995 | 79 |
| 1996 | 79 |
| 1997 | 93 |
| 1998 | 113 |
| 1999 | 53 |
| 2000 | 71 |
| 2001 | 117 |
| 2002 | 66 |
| 2003 | 69 |
| 2004 | 91 |
| 2005 | 75 |
| 2006 | 66 |
| 2007 | 53 |
| 2008 | 49 |
| 2009 | 42 |
| 2010 | 46 |
| 2011 | 29 |
| 2012 | 34 |
| 2013 | 12 |
| 2014 | 7 |
| 2016 | 38 |
| 2017 | 15 |
| 2019 | 9 |
| 2020 | 5 |
| 2021 | 5 |
| 2023 | 6 |