| Year | Count |
|---|---|
| 1977 | 11 |
| 1978 | 5 |
| 1979 | 17 |
| 1981 | 31 |
| 1982 | 40 |
| 1983 | 31 |
| 1984 | 50 |
| 1985 | 43 |
| 1986 | 15 |
| 1987 | 34 |
| 1988 | 16 |
| 1989 | 57 |
| 1990 | 108 |
| 1991 | 41 |
| 1992 | 47 |
| 1993 | 93 |
| 1994 | 135 |
| 1995 | 99 |
| 1996 | 82 |
| 1997 | 94 |
| 1998 | 33 |
| 1999 | 99 |
| 2000 | 61 |
| 2001 | 48 |
| 2002 | 56 |
| 2003 | 60 |
| 2004 | 65 |
| 2005 | 24 |
| 2006 | 25 |
| 2007 | 51 |
| 2008 | 25 |
| 2010 | 6 |
| 2013 | 10 |