CREATE TABLE table_34660 ("Year" FLOAT, "Class" TEXT, "Team" TEXT, "Points" FLOAT, "Wins" FLOAT)

Class of 500cc, and a Wins smaller than 0 had what average year?
SELECT AVG("Year") FROM table_34660 WHERE "Class" = '500cc' AND "Wins" < '0'
SELECT AVG("Year") FROM "table_34660" WHERE "Class" = '500cc' AND "Wins" < '0'