user: ### NOW ANSWER:
Question: What is the year of the Lotus 25 chassis?
Columns: ['Year', 'Entrant', 'Chassis', 'Engine', 'Pts.']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1960.0, 'Team Lotus', 'Lotus 18', 'Climax I4', '8']
SQL:

assistant: SELECT AVG("Year") FROM "Table" WHERE "Chassis" = 'Lotus 25';