| Year | Count |
|---|---|
| 1974 | 10 |
| 1975 | 10 |
| 1976 | 8 |
| 1977 | 27 |
| 1978 | 23 |
| 1979 | 16 |
| 1980 | 10 |
| 1981 | 5 |
| 1982 | 10 |
| 1983 | 9 |
| 1986 | 7 |
| 1987 | 5 |
| 1989 | 6 |
| 1990 | 18 |
| 1991 | 10 |
| 1992 | 16 |
| 1993 | 119 |
| 1994 | 98 |
| 1995 | 78 |
| 1996 | 62 |
| 1997 | 107 |
| 1998 | 50 |
| 1999 | 66 |
| 2000 | 46 |
| 2001 | 63 |
| 2002 | 35 |
| 2003 | 38 |
| 2004 | 23 |
| 2005 | 7 |
| 2006 | 45 |
| 2007 | 11 |
| 2008 | 6 |
| 2015 | 10 |
| 2017 | 5 |
| 2019 | 10 |
| 2020 | 5 |