Make contents in legend in ASCENDING order

Include the GROUPORDER=ASCENDING option in the VBARPARM statements.  For example:

vbarparm category=subject response=&var / 
      group=&group datalabel=&byvar dataskin=pressed datalabelattrs=(size=6 weight=bold)
     groupdisplay=cluster clusterwidth=1 grouporder=ascending;

or

keylegend / location=inside position=topright title="Highest Grade" sortorder=ascending;