| Year | Participants | No. of dropouts | Stage of first dropout |
|---|---|---|---|
| 2020 | 95 | 15 | 2 |
| 2019 | 89 | 22 | 1 |
| 2018 | 101 | 25 | 1 |
| 2017 | 104 | 8 | 1 |
| 2016 | 96 | 8 | 1 |
| 2015 | 94 | 22 | 0 |
| 2014 | 96 | 10 | 1 |
| 2011 | 103 | 31 | 1 |
| 2009 | 96 | 18 | 6 |
| 2008 | 90 | ||
| 2007 | 93 | 19 | 1 |
| 2006 | 95 | 9 | 3 |
| 2005 | 144 | 23 | 2 |
| 2004 | 85 | ||
| 2003 | 85 | 3 | 3 |
| 2002 | 80 | 12 | 1 |
| 2001 | 80 | 13 | 5 |
| 2000 | 80 | 4 | 13 |
| 1999 | 75 | ||
| 1998 | 18 | ||
| 1997 | 6 | ||
| 1996 | 9 | ||
| 1995 | 12 | ||
| 1994 | 13 | ||
| 1993 | 14 | ||
| 1992 | 11 | ||
| 1991 | 11 | ||
| 1990 | 12 | ||
| 1989 | 11 | ||
| 1988 | 11 | ||
| 1987 | 14 | ||
| 1986 | 8 | ||
| 1985 | 9 | ||
| 1984 | 11 | ||
| 1983 | 9 | ||
| 1982 | 12 | ||
| 1981 | 9 | ||
| 1980 | 5 | ||
| 1979 | 8 | ||
| 1978 | 10 | ||
| 1977 | 3 | ||
| 1976 | 3 | ||
| 1975 | 3 | ||
| 1974 | 2 | ||
| 1973 | 2 | ||
| 1972 | 1 | ||
| 1971 | 2 | ||
| 1970 | 3 | ||
| 1969 | 3 | ||
| 1968 | 4 | ||
| 1967 | 1 |