user: Question: What is the average year of events that took place in antwerp, belgium?
Columns: ['Year', 'Competition', 'Venue', 'Position', 'Notes']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1985.0, 'World Cross Country Championships', 'Lisbon , Portugal', '2nd', 'Junior race']
SQL:

assistant: SELECT AVG("Year") FROM "Table" WHERE "Venue" = 'antwerp, belgium';