Generate two plots and display them on the same
set of axes. OVERLAY specifies that both plot lines appear on the same
graph. LEGEND= assigns the LEGEND1 definition to the graph.
proc gplot data=reflib.stocks;
plot high*year low*year / overlay legend=legend1
vref=1000 to 5000 by 1000 lvref=2
haxis=axis1 hminor=4
vaxis=axis2 vminor=1;
run;
quit;