1st competition 2-13 July 1964 46 participants from 11 countries 2nd competition 10-23 July 1965 58 participants from 16 countries 3rd competition 16-30 July 1966 48 participants from 9 countries 4th competition 8-20 July 1968 61 participants from 18 countries 5th competition 12-25 July 1970 74 participants from 17 countries 6th competition 11-26 July 1972 71 participants from 16 countries 7th competition 8-25 July 1974 115 participants from 24 countries 8th competition 10-25 July 1976 133 participants from 27 countries 9th competition 10-25 July 1978 151 participants from 27 countries 10th competition 1-18 July 1980 140 participants from 21 countries 11th competition 9-24 July 1983 156 participants from 23 countries

12th competition 12-28 July 1986 125 participants from 25 countries 13th competition 13-30 July 1988 134 participants from 27 countries 14th competition 14-31 July 1990 86 participants from 19 countries 15th competition 15-30 July 1992 121 participants from 28 countries 16th competition 15-30 July 1994 154 participants from 29 countries 17th competition 15-23 July 1996 142 participants from 30 countries 18th competition 18-29 July 1998 154 participants from 30 countries 19th competition 19-30 July 2000 145 participants from 29 countries 20th competition 15-30 July 2002 142 participants from 32 countries 21th competition 15-30 July 2004 137 participants from 30 countries 22th competition 15-30 July 2006 181 participants from 32 countries 23th competition 15-30 July 2008 137 participants from 27 countries