CREATE TABLE table_68396 ("Year" FLOAT, "Entrant" TEXT, "Chassis" TEXT, "Engine" TEXT, "Points" FLOAT)

What year shows the Entrant of bmw motorsport?
SELECT SUM("Year") FROM table_68396 WHERE "Entrant" = 'bmw motorsport'
SELECT SUM("Year") FROM "table_68396" WHERE "Entrant" = 'bmw motorsport'