CREATE TABLE table_15008 ("Film" TEXT, "Year" FLOAT, "Score composer" TEXT, "U.K. peak position" TEXT, "U.S. peak position" TEXT)

What was the US Peak position of the film that peaked at #21 in the UK?
SELECT "U.S. peak position" FROM table_15008 WHERE "U.K. peak position" = '21'
SELECT "U.S. peak position" FROM "table_15008" WHERE "U.K. peak position" = '21'