SELECT account, ClassCode, SUM(amount) AS subtotal ;
	FROM mytable ;
	GROUP BY account, ClassCode ;
	INTO CURSORS crsST

SELECT mt.account, mt.amount, ROUND(mt.amount/st.subtotal,2) AS percentage 	
	FROM mytable mt ;
	JOIN crsST st ON st.account+st.ClassCode = mt.account+mt.ClassCode ;
	INTO CURSOR crsResult