I think you want a pipelined table function.
Something like this:
CREATE OR REPLACE PACKAGE test AS
TYPE measure_record IS RECORD(
l4_id VARCHAR2(50),
l6_id VARCHAR2(50),
l8_id VARCHAR2(50),
year NUMBER,
period NUMBER,
VALUE NUMBER);
TYPE measure_table IS TABLE OF measure_record;
FUNCTION get_ups(foo NUMBER)
RETURN measure_table
PIPELINED;
END;
CREATE OR REPLACE PACKAGE BODY test AS
FUNCTION get_ups(foo number)
RETURN measure_table
PIPELINED IS
rec measure_record;
BEGIN
SELECT 'foo', 'bar', 'baz', 2010, 5, 13
INTO rec
FROM DUAL;
-- you would usually have a cursor and a loop here
PIPE ROW (rec);
RETURN;
END get_ups;
END;
For simplicity I removed your parameters and didn't implement a loop in the function, but you can see the principle.
Usage:
SELECT *
FROM table(test.get_ups(0));
L4_ID L6_ID L8_ID YEAR PERIOD VALUE
----- ----- ----- ---------- ---------- ----------
foo bar baz 2010 5 13
1 row selected.