CREATE TABLE table_28595 ("Location" TEXT, "Date" FLOAT, "Denomination" TEXT, "Coinage metal" TEXT, "Mintage" FLOAT, "KM number" TEXT)

What is the maximum date for a mintage of 150 and a KM number of S66?
SELECT MAX("Date") FROM table_28595 WHERE "Mintage" = '150' AND "KM number" = 'S66'
SELECT MAX("Date") FROM "table_28595" WHERE "KM number" = 'S66' AND "Mintage" = '150'