| Year | Count |
|---|---|
| 1960 | 6 |
| 1977 | 5 |
| 1978 | 5 |
| 1979 | 10 |
| 1980 | 6 |
| 1981 | 20 |
| 1982 | 13 |
| 1983 | 8 |
| 1985 | 27 |
| 1986 | 10 |
| 1987 | 17 |
| 1988 | 21 |
| 1989 | 25 |
| 1990 | 34 |
| 1991 | 43 |
| 1992 | 50 |
| 1993 | 58 |
| 1994 | 70 |
| 1995 | 44 |
| 1996 | 54 |
| 1997 | 30 |
| 1998 | 29 |
| 1999 | 46 |
| 2000 | 43 |
| 2001 | 46 |
| 2002 | 23 |
| 2003 | 10 |
| 2004 | 28 |
| 2005 | 6 |
| 2006 | 36 |
| 2008 | 5 |
| 2010 | 10 |
| 2018 | 10 |