| Year | Participants | No. of dropouts | Stage of first dropout |
|---|---|---|---|
| 2020 | 110 | 13 | 1 |
| 2019 | 131 | 28 | 0 |
| 2018 | 113 | 7 | 3 |
| 2017 | 121 | 21 | 1 |
| 2016 | 111 | 16 | 1 |
| 2015 | 135 | 29 | 1 |
| 2014 | 131 | 32 | 1 |
| 2013 | 119 | 26 | 1 |
| 2012 | 123 | 24 | 1 |
| 2011 | 114 | 50 | 1 |
| 2010 | 129 | 50 | 3 |
| 2009 | 120 | ||
| 2008 | 118 | ||
| 2007 | 76 | ||
| 2006 | 25 | ||
| 2005 | 34 | ||
| 2004 | 31 | ||
| 2003 | 75 | ||
| 2002 | 10 | ||
| 2001 | 36 | ||
| 2000 | 27 | ||
| 1999 | 16 | ||
| 1998 | 17 | ||
| 1997 | 19 | ||
| 1996 | 8 | ||
| 1995 | 14 | ||
| 1994 | 14 | ||
| 1993 | 8 | ||
| 1992 | 5 | ||
| 1991 | 13 | ||
| 1990 | 11 | ||
| 1989 | 12 | ||
| 1988 | 11 | ||
| 1987 | 9 | ||
| 1986 | 12 | ||
| 1985 | 7 | ||
| 1984 | 3 | ||
| 1983 | 6 | ||
| 1982 | 10 | ||
| 1981 | 1 | ||
| 1980 | 1 | ||
| 1979 | 1 | ||
| 1978 | 1 |