user: Question: What is average year for Ayan Mukerji?
Columns: ['Rank', 'Movie', 'Year', 'Worldwide Gross', 'Director', 'Verdict']
Types: ['real', 'text', 'real', 'text', 'text', 'text']
Sample row: [1.0, '3 Idiots', 2009.0, '392 crore ()', 'Rajkumar Hirani', 'All Time Blockbuster']
SQL:

assistant: SELECT AVG("Year") FROM "Table" WHERE "Director" = 'Ayan Mukerji';