| Year | Count |
|---|---|
| 1977 | 18 |
| 1978 | 6 |
| 1981 | 5 |
| 1982 | 5 |
| 1983 | 13 |
| 1984 | 9 |
| 1986 | 37 |
| 1987 | 30 |
| 1988 | 25 |
| 1989 | 15 |
| 1990 | 49 |
| 1991 | 7 |
| 1992 | 47 |
| 1993 | 30 |
| 1994 | 61 |
| 1995 | 35 |
| 1996 | 44 |
| 1997 | 89 |
| 1998 | 54 |
| 1999 | 53 |
| 2000 | 80 |
| 2001 | 66 |
| 2002 | 37 |
| 2003 | 85 |
| 2004 | 67 |
| 2005 | 69 |
| 2006 | 81 |
| 2007 | 56 |
| 2008 | 30 |
| 2009 | 5 |
| 2010 | 16 |
| 2011 | 18 |
| 2012 | 14 |
| 2013 | 5 |
| 2016 | 9 |
| 2017 | 7 |
| 2019 | 7 |