CREATE TABLE table_37311 ("Year" FLOAT, "Class" CLOB, "Team" CLOB, "Points" FLOAT, "Wins" FLOAT)

In what Year did the Norton Team have 0 Points and 350cc Class?
SELECT AVG("Year") FROM table_37311 WHERE "Class" = '350cc' AND "Team" = 'norton' AND "Points" < '0'
SELECT AVG("Year") FROM "table_37311" WHERE "Class" = '350cc' AND "Points" < '0' AND "Team" = 'norton'