data work.profit;
   set ia.dnunder;
   set ia.sale2000(keep = RouteID FlightID Date Rev1st
                          RevBusiness RevEcon RevCargo)
                          key = FlightDate;
   Profit = sum(Rev1st, RevBusiness, RevEcon, RevCargo,
                - Expenses);
run;

proc print data = work.profit;
   title 'Profit for the Flights to Australia and New Zealand';
run;