Complex sentence: In November 2003 the age group was lowered to 35 years; in June 2004 to 30 years old; in December 2004 to 25 years old and in March 2005 to 20 years old.
Split into simpler sentences: In November 2003 the age group was lowered to 35 years. In June 2004, the age group was lowered to 30 years old.