set serveroutput on  
declare   
event_level number;  
begin   
for i in 10000..10999 loop      
sys.dbms_system.read_ev(i,event_level);      
if (event_level > 0) then         
dbms_output.put_line('Event '||to_char(i)||' set at level '||to_char(event_level));      
end if;   
end loop;  
end;  
/