CREATE TABLE table_68916 ("Year" FLOAT, "Theme" TEXT, "Artist" TEXT, "Mintage" TEXT, "Issue price" FLOAT, "Special notes" TEXT)

What theme has a mintage of 3527?
SELECT "Theme" FROM table_68916 WHERE "Mintage" = '3527'
SELECT "Theme" FROM "table_68916" WHERE "Mintage" = '3527'