CREATE TABLE table_68627 ("Year" FLOAT, "Team" CLOB, "Chassis" CLOB, "Engine" CLOB, "Points" FLOAT)

What year was a Rial Arc2 chassis used?
SELECT SUM("Year") FROM table_68627 WHERE "Chassis" = 'rial arc2'
SELECT SUM("Year") FROM "table_68627" WHERE "Chassis" = 'rial arc2'