pl/sql Query will not run - sql

Question

I am just learning PL/SQL and I can't understand why the statement within this loop runs on its own, but the PL/SQL procedure executes without any results showing at all. Is anyone able to give me any advice? Thanks.
set serveroutput on size 2000
DECLARE
CURSOR money_cur IS
SELECT SUM(etotal) AS Total_income
FROM a_enrolment
GROUP BY etotal;
etotal a_enrolment%ROWTYPE;
total_income number;
BEGIN
DBMS_OUTPUT.PUT_LINE( chr(10) );
DBMS_OUTPUT.PUT_LINE( 'Displaying total income generated' || chr(10) );
FOR etotal IN money_cur LOOP
DBMS_OUTPUT.PUT_LINE('Total income is ' || Total_income);
END LOOP;
END;
/

Answer 1

DECLARE
CURSOR money_cur IS
SELECT SUM(etotal) AS Total_income
FROM a_enrolment
GROUP BY etotal;
--etotal a_enrolment%ROWTYPE;
--total_income number;
BEGIN
DBMS_OUTPUT.PUT_LINE( chr(10) );
DBMS_OUTPUT.PUT_LINE( 'Displaying total income generated' || chr(10) );
FOR etotal IN money_cur LOOP
DBMS_OUTPUT.PUT_LINE('Total income is ' || etotal.Total_income);
END LOOP;
END;
/

Answer 2

Thank you everyone for your help :) I really appreciate it. Below is another way I found I could solve the problem in case any of you ever face a similar issue.
DECLARE
CURSOR student_cur IS
SELECT sid, etotal, edate
FROM a_enrolment
ORDER BY sID;
grand_total number := 0;
total a_enrolment%ROWTYPE;
BEGIN -- this whole block is the proceedure
DBMS_OUTPUT.PUT_LINE( chr(10) );
DBMS_OUTPUT.PUT_LINE( 'Displaying student details' || chr(10) );
DBMS_OUTPUT.PUT_LINE(RPAD('ID',15) || RPAD('TOTAL',15) || 'DATE');
FOR total IN student_cur LOOP
DBMS_OUTPUT.PUT_LINE(RPAD(total.sID, 15) || RPAD(total.etotal, 15) ||
total.edate);
grand_total := grand_total + total.etotal; -- this is the function
END LOOP;
DBMS_OUTPUT.PUT_LINE('The grand total is $' || grand_total);
EXCEPTION
WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE('No data has been returned');
WHEN TOO_MANY_ROWS THEN
DBMS_OUTPUT.PUT_LINE('Too much data has been returned');
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE('Oracle error code: ' || SQLCODE || ' - Message: ' ||
SQLERRM);
END;
/