| Year | Count |
|---|---|
| 1978 | 5 |
| 1981 | 11 |
| 1982 | 10 |
| 1983 | 5 |
| 1985 | 5 |
| 1986 | 10 |
| 1987 | 5 |
| 1988 | 15 |
| 1989 | 14 |
| 1990 | 8 |
| 1991 | 21 |
| 1992 | 47 |
| 1993 | 25 |
| 1994 | 105 |
| 1995 | 78 |
| 1996 | 64 |
| 1997 | 120 |
| 1998 | 71 |
| 1999 | 77 |
| 2000 | 99 |
| 2001 | 127 |
| 2002 | 81 |
| 2003 | 45 |
| 2004 | 19 |
| 2005 | 35 |
| 2006 | 15 |
| 2007 | 32 |
| 2008 | 12 |
| 2010 | 5 |
| 2011 | 10 |
| 2013 | 13 |
| 2015 | 5 |