user: ### NOW ANSWER:
Question: What year was a Rial ARC2 chassis used?
Columns: ['Year', 'Team', 'Chassis', 'Engine', 'Points']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1985.0, 'West Zakspeed Racing', 'Zakspeed 841', 'Zakspeed 1500/4 1.5 L4T', 0.0]
SQL:

assistant: SELECT SUM("Year") FROM "Table" WHERE "Chassis" = 'Rial ARC2';