CREATE TABLE table_14475 ("Year" FLOAT, "Entrant" TEXT, "Chassis" TEXT, "Engine" TEXT, "Points" TEXT)

What year was the cosworth ca2006 2.4 v8 4 series used?
SELECT AVG("Year") FROM table_14475 WHERE "Engine" = 'cosworth ca2006 2.4 v8 4 series'
SELECT AVG("Year") FROM "table_14475" WHERE "Engine" = 'cosworth ca2006 2.4 v8 4 series'