Why does this plpgslq always return 1?

Can anyone tell me why this always return 1?  Thanks!

CREATE FUNCTION passrate(date, date, text) RETURNS float AS '

DECLAREbegindate ALIAS FOR $1;enddate ALIAS FOR $2;passfail ALIAS FOR $3; ret float;countp float;counttotal float;

BEGIN
SELECT INTO countp COUNT(*)FROM benchmarkWHERE passfail = passfail;
SELECT INTO counttotal COUNT(*)FROM benchmark;
ret := countp / counttotal;RETURN ret;
END;'
LANGUAGE 'plpgsql';


John