Generate the contour plot. HMINOR=0 sets the number of minor tick marks on the horizontal axis to 0. The LLEVELS= option lists a line type for each contour line. The number of line types listed correspond to the number of contour levels specified in the NLEVELS= option. NLEVELS=6 specifies the number of levels to compute for z. The NAME= option specifies the name of the catalog entry for the plot. The VAXIS= option assigns the AXIS1 statement to the vertical axis. VMINOR=0 sets the number of minor tick marks on the vertical axis to 0.

proc gcontour data=pollen;
    plot week*workdays=pollen/
       hminor=0
       llevels= 2 20 21 33 25 41
       name="GCTNLVEL"
       nlevels=6
       vaxis=axis1
       vminor=0; 
    run;
 quit;