| Year | Count |
|---|---|
| 1972 | 12 |
| 1973 | 12 |
| 1974 | 29 |
| 1975 | 12 |
| 1976 | 18 |
| 1977 | 35 |
| 1978 | 24 |
| 1979 | 32 |
| 1981 | 18 |
| 1983 | 10 |
| 1984 | 10 |
| 1988 | 5 |
| 1989 | 10 |
| 1990 | 12 |
| 1991 | 35 |
| 1993 | 5 |
| 1994 | 7 |
| 1995 | 5 |
| 1996 | 11 |
| 1997 | 7 |
| 1998 | 15 |
| 1999 | 36 |
| 2000 | 17 |
| 2001 | 15 |
| 2002 | 16 |
| 2003 | 36 |
| 2004 | 20 |
| 2005 | 13 |
| 2006 | 5 |
| 2008 | 10 |
| 2010 | 14 |
| 2011 | 16 |
| 2013 | 17 |
| 2015 | 16 |
| 2017 | 14 |
| 2019 | 5 |