| Year | Count |
|---|---|
| 1974 | 5 |
| 1978 | 10 |
| 1978 | 7 |
| 1980 | 5 |
| 1981 | 5 |
| 1982 | 5 |
| 1983 | 5 |
| 1987 | 5 |
| 1988 | 5 |
| 1988 | 12 |
| 1989 | 6 |
| 1989 | 9 |
| 1990 | 7 |
| 1991 | 8 |
| 1991 | 9 |
| 1992 | 6 |
| 1992 | 10 |
| 1993 | 6 |
| 1993 | 16 |
| 1995 | 8 |
| 1996 | 8 |
| 1997 | 6 |
| 1997 | 16 |
| 1998 | 6 |
| 1998 | 5 |
| 1999 | 5 |
| 2002 | 6 |
| 2004 | 5 |
| 2006 | 5 |
| 2006 | 5 |
| 2008 | 5 |
| 2011 | 6 |
| 2012 | 6 |
| 2014 | 8 |
| 2016 | 15 |