CREATE TABLE table_72171 ("Round" FLOAT, "Grand Prix" TEXT, "Pole Position" TEXT, "Fastest Lap" TEXT, "Winning Driver" TEXT, "Winning Constructor" TEXT, "Report" TEXT)

How many drivers won the Italian Grand Prix?
SELECT COUNT("Winning Driver") FROM table_72171 WHERE "Grand Prix" = 'Italian Grand Prix'
SELECT COUNT("Winning Driver") FROM "table_72171" WHERE "Grand Prix" = 'Italian Grand Prix'