Produce the block maps. The FORMAT statements assign POPFMT. to the POP variable and $REGIONFMT. to the REGION variable. The AREA statement assigns patterns to the map areas according to the values of the REGION variable. The RELZERO option specifies that the blocks values are relative to zero.

proc gmap map=maps.us data=sashelp.zipcode all;
   id state;
   block zip / statistic=frequency
                     levels=5 relzero;
run;
quit;