user: ### NOW ANSWER:
Question: What year was the Cosworth CA2006 2.4 V8 4 Series used?
Columns: ['Year', 'Entrant', 'Chassis', 'Engine', 'Points']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1997.0, 'Mild Seven Benetton Renault', 'Benetton B197', 'Renault RS9 3.0 V10', '4']
SQL:

assistant: SELECT AVG("Year") FROM "Table" WHERE "Engine" = 'Cosworth CA2006 2.4 V8 4 Series';