perl -ane '{print $F[5]," ",$F[6],"\n";}' < dat.txt
-135.185 178.150
-49.668 -31.158
... snip
-81.417 52.986
-83.126 -56.051

##</code><code>##

perl -ane '{$t5+=$F[5]; $t6+=$F[6]; $t+=1}
         END{print $t5/$t," ",$t6/$t,"\n";}' < dat.txt

-85.6206666666667 30.2721333333333

##</code><code>##

 perl -ane '{$t5{$F[3]}+=$F[5]; $t6{$F[3]}+=$F[6]; $t{$F[3]}+=1} 
                  END{foreach $i (keys %t5) 
                          {print "Group $i ",$t5{$i}/$t{$i}," ",$t6{$i}/$t{$i},"\n";}}  ' < dat.txt
Group S -75.969 10.2868
Group G -108.8372 73.3412
Group M -72.0558 7.1884