CREATE TABLE table_59672 ("Class" TEXT, "Quantity" FLOAT, "Type" TEXT, "Delivered" TEXT, "K.B.Sts.B. Class" TEXT, "Retired" TEXT)

What is the highest quantity of the b ix k.b.sts.b.?
SELECT MAX("Quantity") FROM table_59672 WHERE "K.B.Sts.B. Class" = 'b ix'
SELECT MAX("Quantity") FROM "table_59672" WHERE "K.B.Sts.B. Class" = 'b ix'