Generate two plots and display them on the same set of axes. The OVERLAY option specifies that both plot lines appear on the same graph. The LEGEND= option assigns the LEGEND1 definition to the graph. The VAXIS= option sets major tick marks for the vertical axis. The HMINOR= and VMINOR= options specify the number of tick marks between major tick marks.

proc gplot data=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;