user: Question: What's the average Year for the Position of 7th (sf)?
Columns: ['Year', 'Competition', 'Venue', 'Position', 'Event']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [2000.0, 'World Junior Championships', 'Santiago de Chile', '3rd', '800 m']
SQL:

assistant: SELECT AVG("Year") FROM "Table" WHERE "Position" = '7th (sf)';