| Year | Count |
|---|---|
| 1969 | 6 |
| 1970 | 13 |
| 1972 | 13 |
| 1973 | 23 |
| 1974 | 9 |
| 1975 | 5 |
| 1977 | 10 |
| 1978 | 8 |
| 1979 | 10 |
| 1980 | 5 |
| 1981 | 5 |
| 1984 | 8 |
| 1988 | 15 |
| 1991 | 5 |
| 1992 | 5 |
| 1993 | 7 |
| 1994 | 24 |
| 1995 | 17 |
| 1997 | 25 |
| 1998 | 11 |
| 1999 | 16 |
| 2000 | 23 |
| 2001 | 24 |
| 2003 | 5 |
| 2004 | 6 |
| 2006 | 16 |
| 2008 | 12 |
| 2009 | 17 |
| 2011 | 12 |
| 2012 | 10 |
| 2013 | 10 |
| 2015 | 12 |
| 2018 | 10 |
| 2022 | 10 |